The Tor Browser: layout/base/nsCSSFrameConstructor.cpp@b8a032363ba2 (annotated)

layout/base/nsCSSFrameConstructor.cpp@b8a032363ba2 (annotated)

layout/base/nsCSSFrameConstructor.cpp

Thu, 22 Jan 2015 13:21:57 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 22 Jan 2015 13:21:57 +0100
branch: TOR_BUG_9701
changeset 15: b8a032363ba2
permissions: -rw-r--r--

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 // vim:cindent:ts=2:et:sw=2:
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 /*
  * construction of a frame tree that is nearly isomorphic to the content
  * tree and updating of that tree in response to dynamic changes
  */
 #include "nsCSSFrameConstructor.h"
 #include "mozilla/AutoRestore.h"
 #include "mozilla/DebugOnly.h"
 #include "mozilla/dom/HTMLSelectElement.h"
 #include "mozilla/EventStates.h"
 #include "mozilla/Likely.h"
 #include "mozilla/LinkedList.h"
 #include "nsAbsoluteContainingBlock.h"
 #include "nsIAtom.h"
 #include "nsIFrameInlines.h"
 #include "nsGkAtoms.h"
 #include "nsPresContext.h"
 #include "nsIDocument.h"
 #include "nsTableFrame.h"
 #include "nsTableColFrame.h"
 #include "nsIDOMHTMLDocument.h"
 #include "nsHTMLParts.h"
 #include "nsIPresShell.h"
 #include "nsUnicharUtils.h"
 #include "nsStyleSet.h"
 #include "nsViewManager.h"
 #include "nsStyleConsts.h"
 #include "nsIDOMXULElement.h"
 #include "nsContainerFrame.h"
 #include "nsNameSpaceManager.h"
 #include "nsIComboboxControlFrame.h"
 #include "nsIListControlFrame.h"
 #include "nsIDOMCharacterData.h"
 #include "nsPlaceholderFrame.h"
 #include "nsTableRowGroupFrame.h"
 #include "nsIFormControl.h"
 #include "nsCSSAnonBoxes.h"
 #include "nsTextFragment.h"
 #include "nsIAnonymousContentCreator.h"
 #include "nsBindingManager.h"
 #include "nsXBLBinding.h"
 #include "nsContentUtils.h"
 #include "nsIScriptError.h"
 #ifdef XP_MACOSX
 #include "nsIDocShell.h"
 #endif
 #include "ChildIterator.h"
 #include "nsError.h"
 #include "nsLayoutUtils.h"
 #include "nsAutoPtr.h"
 #include "nsBoxFrame.h"
 #include "nsBoxLayout.h"
 #include "nsFlexContainerFrame.h"
 #include "nsGridContainerFrame.h"
 #include "nsImageFrame.h"
 #include "nsIObjectLoadingContent.h"
 #include "nsTArray.h"
 #include "nsGenericDOMDataNode.h"
 #include "mozilla/dom/Element.h"
 #include "nsAutoLayoutPhase.h"
 #include "nsStyleStructInlines.h"
 #include "nsPageContentFrame.h"
 #include "RestyleManager.h"
 #include "StickyScrollContainer.h"
 #include "nsFieldSetFrame.h"
 #ifdef MOZ_XUL
 #include "nsIRootBox.h"
 #endif
 #ifdef ACCESSIBILITY
 #include "nsAccessibilityService.h"
 #endif
 #include "nsBlockFrame.h"
 #include "nsIScrollableFrame.h"
 #include "nsXBLService.h"
 #undef NOISY_FIRST_LETTER
 #include "nsMathMLParts.h"
 #include "mozilla/dom/SVGTests.h"
 #include "nsSVGUtils.h"
 #include "nsRefreshDriver.h"
 #include "nsRuleProcessorData.h"
 #include "nsTextNode.h"
 using namespace mozilla;
 using namespace mozilla::dom;
 // An alias for convenience.
 static const nsIFrame::ChildListID kPrincipalList = nsIFrame::kPrincipalList;
 nsIFrame*
 NS_NewHTMLCanvasFrame (nsIPresShell* aPresShell, nsStyleContext* aContext);
 nsIFrame*
 NS_NewHTMLVideoFrame (nsIPresShell* aPresShell, nsStyleContext* aContext);
 nsIFrame*
 NS_NewSVGOuterSVGFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
 nsIFrame*
 NS_NewSVGOuterSVGAnonChildFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
 nsIFrame*
 NS_NewSVGInnerSVGFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
 nsIFrame*
 NS_NewSVGPathGeometryFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
 nsIFrame*
 NS_NewSVGGFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
 nsIFrame*
 NS_NewSVGGenericContainerFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
 nsIFrame*
 NS_NewSVGForeignObjectFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
 nsIFrame*
 NS_NewSVGAFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
 nsIFrame*
 NS_NewSVGSwitchFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
 nsIFrame*
 NS_NewSVGTextFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
 nsIFrame*
 NS_NewSVGContainerFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
 nsIFrame*
 NS_NewSVGUseFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
 nsIFrame*
 NS_NewSVGViewFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
 extern nsIFrame*
 NS_NewSVGLinearGradientFrame(nsIPresShell *aPresShell, nsStyleContext* aContext);
 extern nsIFrame*
 NS_NewSVGRadialGradientFrame(nsIPresShell *aPresShell, nsStyleContext* aContext);
 extern nsIFrame*
 NS_NewSVGStopFrame(nsIPresShell *aPresShell, nsStyleContext* aContext);
 nsIFrame*
 NS_NewSVGMarkerFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
 nsIFrame*
 NS_NewSVGMarkerAnonChildFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
 extern nsIFrame*
 NS_NewSVGImageFrame(nsIPresShell *aPresShell, nsStyleContext* aContext);
 nsIFrame*
 NS_NewSVGClipPathFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
 nsIFrame*
 NS_NewSVGFilterFrame(nsIPresShell *aPresShell, nsStyleContext* aContext);
 nsIFrame*
 NS_NewSVGPatternFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
 nsIFrame*
 NS_NewSVGMaskFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
 nsIFrame*
 NS_NewSVGFEContainerFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
 nsIFrame*
 NS_NewSVGFELeafFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
 nsIFrame*
 NS_NewSVGFEImageFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
 nsIFrame*
 NS_NewSVGFEUnstyledLeafFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
 #include "nsINodeInfo.h"
 #include "prenv.h"
 #include "nsNodeInfoManager.h"
 #include "nsContentCreatorFunctions.h"
 #ifdef DEBUG
 // Set the environment variable GECKO_FRAMECTOR_DEBUG_FLAGS to one or
 // more of the following flags (comma separated) for handy debug
 // output.
 static bool gNoisyContentUpdates = false;
 static bool gReallyNoisyContentUpdates = false;
 static bool gNoisyInlineConstruction = false;
 struct FrameCtorDebugFlags {
   const char* name;
   bool* on;
 };
 static FrameCtorDebugFlags gFlags[] = {
   { "content-updates",              &gNoisyContentUpdates },
   { "really-noisy-content-updates", &gReallyNoisyContentUpdates },
   { "noisy-inline",                 &gNoisyInlineConstruction }
 };
 #define NUM_DEBUG_FLAGS (sizeof(gFlags) / sizeof(gFlags[0]))
 #endif
 #ifdef MOZ_XUL
 #include "nsMenuFrame.h"
 #include "nsPopupSetFrame.h"
 #include "nsTreeColFrame.h"
 #include "nsIBoxObject.h"
 #include "nsPIListBoxObject.h"
 #include "nsListBoxBodyFrame.h"
 #include "nsListItemFrame.h"
 #include "nsXULLabelFrame.h"
 //------------------------------------------------------------------
 nsIFrame*
 NS_NewAutoRepeatBoxFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
 nsIFrame*
 NS_NewRootBoxFrame (nsIPresShell* aPresShell, nsStyleContext* aContext);
 nsIFrame*
 NS_NewDocElementBoxFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
 nsIFrame*
 NS_NewThumbFrame (nsIPresShell* aPresShell, nsStyleContext* aContext);
 nsIFrame*
 NS_NewDeckFrame (nsIPresShell* aPresShell, nsStyleContext* aContext);
 nsIFrame*
 NS_NewLeafBoxFrame (nsIPresShell* aPresShell, nsStyleContext* aContext);
 nsIFrame*
 NS_NewStackFrame (nsIPresShell* aPresShell, nsStyleContext* aContext);
 nsIFrame*
 NS_NewProgressMeterFrame (nsIPresShell* aPresShell, nsStyleContext* aContext);
 nsIFrame*
 NS_NewRangeFrame (nsIPresShell* aPresShell, nsStyleContext* aContext);
 nsIFrame*
 NS_NewImageBoxFrame (nsIPresShell* aPresShell, nsStyleContext* aContext);
 nsIFrame*
 NS_NewTextBoxFrame (nsIPresShell* aPresShell, nsStyleContext* aContext);
 nsIFrame*
 NS_NewGroupBoxFrame (nsIPresShell* aPresShell, nsStyleContext* aContext);
 nsIFrame*
 NS_NewButtonBoxFrame (nsIPresShell* aPresShell, nsStyleContext* aContext);
 nsIFrame*
 NS_NewSplitterFrame (nsIPresShell* aPresShell, nsStyleContext* aContext);
 nsIFrame*
 NS_NewMenuPopupFrame (nsIPresShell* aPresShell, nsStyleContext* aContext);
 nsIFrame*
 NS_NewPopupSetFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
 nsIFrame*
 NS_NewMenuFrame (nsIPresShell* aPresShell, nsStyleContext* aContext, uint32_t aFlags);
 nsIFrame*
 NS_NewMenuBarFrame (nsIPresShell* aPresShell, nsStyleContext* aContext);
 nsIFrame*
 NS_NewTreeBodyFrame (nsIPresShell* aPresShell, nsStyleContext* aContext);
 // grid
 nsresult
 NS_NewGridLayout2 ( nsIPresShell* aPresShell, nsBoxLayout** aNewLayout );
 nsIFrame*
 NS_NewGridRowLeafFrame (nsIPresShell* aPresShell, nsStyleContext* aContext);
 nsIFrame*
 NS_NewGridRowGroupFrame (nsIPresShell* aPresShell, nsStyleContext* aContext);
 // end grid
 nsIFrame*
 NS_NewTitleBarFrame (nsIPresShell* aPresShell, nsStyleContext* aContext);
 nsIFrame*
 NS_NewResizerFrame (nsIPresShell* aPresShell, nsStyleContext* aContext);
 #endif
 nsIFrame*
 NS_NewHTMLScrollFrame (nsIPresShell* aPresShell, nsStyleContext* aContext, bool aIsRoot);
 nsIFrame*
 NS_NewXULScrollFrame (nsIPresShell* aPresShell, nsStyleContext* aContext,
                       bool aIsRoot, bool aClipAllDescendants);
 nsIFrame*
 NS_NewSliderFrame (nsIPresShell* aPresShell, nsStyleContext* aContext);
 nsIFrame*
 NS_NewScrollbarFrame (nsIPresShell* aPresShell, nsStyleContext* aContext);
 nsIFrame*
 NS_NewScrollbarButtonFrame (nsIPresShell* aPresShell, nsStyleContext* aContext);
 #ifdef NOISY_FINDFRAME
 static int32_t FFWC_totalCount=0;
 static int32_t FFWC_doLoop=0;
 static int32_t FFWC_doSibling=0;
 static int32_t FFWC_recursions=0;
 static int32_t FFWC_nextInFlows=0;
 #endif
 // Returns true if aFrame is an anonymous flex item
 static inline bool
 IsAnonymousFlexItem(const nsIFrame* aFrame)
 {
   const nsIAtom* pseudoType = aFrame->StyleContext()->GetPseudo();
   return pseudoType == nsCSSAnonBoxes::anonymousFlexItem;
 }
 static inline nsIFrame*
 GetFieldSetBlockFrame(nsIFrame* aFieldsetFrame)
 {
   // Depends on the fieldset child frame order - see ConstructFieldSetFrame() below.
   nsIFrame* firstChild = aFieldsetFrame->GetFirstPrincipalChild();
   nsIFrame* inner = firstChild && firstChild->GetNextSibling() ? firstChild->GetNextSibling() : firstChild;
   return inner ? inner->GetContentInsertionFrame() : nullptr;
 }
 #define FCDATA_DECL(_flags, _func)                          \
   { _flags, { (FrameCreationFunc)_func }, nullptr, nullptr }
 #define FCDATA_WITH_WRAPPING_BLOCK(_flags, _func, _anon_box)  \
   { _flags | FCDATA_CREATE_BLOCK_WRAPPER_FOR_ALL_KIDS,        \
       { (FrameCreationFunc)_func }, nullptr, &_anon_box }
 //----------------------------------------------------------------------
 /**
  * True if aFrame is an actual inline frame in the sense of non-replaced
  * display:inline CSS boxes.  In other words, it can be affected by {ib}
  * splitting and can contain first-letter frames.  Basically, this is either an
  * inline frame (positioned or otherwise) or an line frame (this last because
  * it can contain first-letter and because inserting blocks in the middle of it
  * needs to terminate it).
  */
 static bool
 IsInlineFrame(const nsIFrame* aFrame)
 {
   return aFrame->IsFrameOfType(nsIFrame::eLineParticipant);
 }
 /**
  * True if aFrame is an instance of an SVG frame class or is an inline/block
  * frame being used for SVG text.
  */
 static bool
 IsFrameForSVG(const nsIFrame* aFrame)
 {
   return aFrame->IsFrameOfType(nsIFrame::eSVG) ||
          aFrame->IsSVGText();
 }
 /**
  * Returns true iff aFrame explicitly prevents its descendants from floating
  * (at least, down to the level of descendants which themselves are
  * float-containing blocks -- those will manage the floating status of any
  * lower-level descendents inside them, of course).
  */
 static bool
 ShouldSuppressFloatingOfDescendants(nsIFrame* aFrame)
 {
   return aFrame->IsFrameOfType(nsIFrame::eMathML) ||
     aFrame->IsBoxFrame() ||
     aFrame->GetType() == nsGkAtoms::flexContainerFrame ||
     aFrame->GetType() == nsGkAtoms::gridContainerFrame;
 }
 /**
  * If any children require a block parent, return the first such child.
  * Otherwise return null.
  */
 static nsIContent*
 AnyKidsNeedBlockParent(nsIFrame *aFrameList)
 {
   for (nsIFrame *k = aFrameList; k; k = k->GetNextSibling()) {
     // Line participants, such as text and inline frames, can't be
     // directly inside a XUL box; they must be wrapped in an
     // intermediate block.
     if (k->IsFrameOfType(nsIFrame::eLineParticipant)) {
       return k->GetContent();
     }
   }
   return nullptr;
 }
 // Reparent a frame into a wrapper frame that is a child of its old parent.
 static void
 ReparentFrame(RestyleManager* aRestyleManager,
               nsIFrame* aNewParentFrame,
               nsIFrame* aFrame)
 {
   aFrame->SetParent(aNewParentFrame);
   aRestyleManager->ReparentStyleContext(aFrame);
 }
 static void
 ReparentFrames(nsCSSFrameConstructor* aFrameConstructor,
                nsIFrame* aNewParentFrame,
                const nsFrameList& aFrameList)
 {
   RestyleManager* restyleManager = aFrameConstructor->RestyleManager();
   for (nsFrameList::Enumerator e(aFrameList); !e.AtEnd(); e.Next()) {
     ReparentFrame(restyleManager, aNewParentFrame, e.get());
   }
 }
 //----------------------------------------------------------------------
 //
 // When inline frames get weird and have block frames in them, we
 // annotate them to help us respond to incremental content changes
 // more easily.
 static inline bool
 IsFramePartOfIBSplit(nsIFrame* aFrame)
 {
   return (aFrame->GetStateBits() & NS_FRAME_PART_OF_IBSPLIT) != 0;
 }
 static nsIFrame* GetIBSplitSibling(nsIFrame* aFrame)
 {
   NS_PRECONDITION(IsFramePartOfIBSplit(aFrame), "Shouldn't call this");
   // We only store the "ib-split sibling" annotation with the first
   // frame in the continuation chain. Walk back to find that frame now.
   return static_cast<nsIFrame*>
     (aFrame->FirstContinuation()->
        Properties().Get(nsIFrame::IBSplitSibling()));
 }
 static nsIFrame* GetIBSplitPrevSibling(nsIFrame* aFrame)
 {
   NS_PRECONDITION(IsFramePartOfIBSplit(aFrame), "Shouldn't call this");
   // We only store the ib-split sibling annotation with the first
   // frame in the continuation chain. Walk back to find that frame now.
   return static_cast<nsIFrame*>
     (aFrame->FirstContinuation()->
        Properties().Get(nsIFrame::IBSplitPrevSibling()));
 }
 static nsIFrame*
 GetLastIBSplitSibling(nsIFrame* aFrame, bool aReturnEmptyTrailingInline)
 {
   for (nsIFrame *frame = aFrame, *next; ; frame = next) {
     next = GetIBSplitSibling(frame);
     if (!next ||
         (!aReturnEmptyTrailingInline && !next->GetFirstPrincipalChild() &&
          !GetIBSplitSibling(next))) {
       NS_ASSERTION(!next || !frame->IsInlineOutside(),
                    "Should have a block here!");
       return frame;
     }
   }
   NS_NOTREACHED("unreachable code");
   return nullptr;
 }
 static void
 SetFrameIsIBSplit(nsIFrame* aFrame, nsIFrame* aIBSplitSibling)
 {
   NS_PRECONDITION(aFrame, "bad args!");
   // We should be the only continuation
   NS_ASSERTION(!aFrame->GetPrevContinuation(),
                "assigning ib-split sibling to other than first continuation!");
   NS_ASSERTION(!aFrame->GetNextContinuation() ||
                IsFramePartOfIBSplit(aFrame->GetNextContinuation()),
                "should have no non-ib-split continuations here");
   // Mark the frame as ib-split.
   aFrame->AddStateBits(NS_FRAME_PART_OF_IBSPLIT);
   if (aIBSplitSibling) {
     NS_ASSERTION(!aIBSplitSibling->GetPrevContinuation(),
                  "assigning something other than the first continuation as the "
                  "ib-split sibling");
     // Store the ib-split sibling (if we were given one) with the
     // first frame in the flow.
     FramePropertyTable* props = aFrame->PresContext()->PropertyTable();
     props->Set(aFrame, nsIFrame::IBSplitSibling(), aIBSplitSibling);
     props->Set(aIBSplitSibling, nsIFrame::IBSplitPrevSibling(), aFrame);
   }
 }
 static nsIFrame*
 GetIBContainingBlockFor(nsIFrame* aFrame)
 {
   NS_PRECONDITION(IsFramePartOfIBSplit(aFrame),
                   "GetIBContainingBlockFor() should only be called on known IB frames");
   // Get the first "normal" ancestor of the target frame.
   nsIFrame* parentFrame;
   do {
     parentFrame = aFrame->GetParent();
     if (! parentFrame) {
       NS_ERROR("no unsplit block frame in IB hierarchy");
       return aFrame;
     }
     // Note that we ignore non-ib-split frames which have a pseudo on their
     // style context -- they're not the frames we're looking for!  In
     // particular, they may be hiding a real parent that _is_ in an ib-split.
     if (!IsFramePartOfIBSplit(parentFrame) &&
         !parentFrame->StyleContext()->GetPseudo())
       break;
     aFrame = parentFrame;
   } while (1);
   // post-conditions
   NS_ASSERTION(parentFrame, "no normal ancestor found for ib-split frame "
                             "in GetIBContainingBlockFor");
   NS_ASSERTION(parentFrame != aFrame, "parentFrame is actually the child frame - bogus reslt");
   return parentFrame;
 }
 //----------------------------------------------------------------------
 // Block/inline frame construction logic. We maintain a few invariants here:
 //
 // 1. Block frames contain block and inline frames.
 //
 // 2. Inline frames only contain inline frames. If an inline parent has a block
 // child then the block child is migrated upward until it lands in a block
 // parent (the inline frames containing block is where it will end up).
 // After this function returns, aLink is pointing to the first link at or
 // after its starting position for which the next frame is a block.  If there
 // is no such link, it points to the end of the list.
 static void
 FindFirstBlock(nsFrameList::FrameLinkEnumerator& aLink)
 {
   for ( ; !aLink.AtEnd(); aLink.Next()) {
     if (!aLink.NextFrame()->IsInlineOutside()) {
       return;
     }
   }
 }
 // This function returns a frame link enumerator pointing to the first link in
 // the list for which the next frame is not block.  If there is no such link,
 // it points to the end of the list.
 static nsFrameList::FrameLinkEnumerator
 FindFirstNonBlock(const nsFrameList& aList)
 {
   nsFrameList::FrameLinkEnumerator link(aList);
   for (; !link.AtEnd(); link.Next()) {
     if (link.NextFrame()->IsInlineOutside()) {
       break;
     }
   }
   return link;
 }
 inline void
 SetInitialSingleChild(nsIFrame* aParent, nsIFrame* aFrame)
 {
   NS_PRECONDITION(!aFrame->GetNextSibling(), "Should be using a frame list");
   nsFrameList temp(aFrame, aFrame);
   aParent->SetInitialChildList(kPrincipalList, temp);
 }
 // -----------------------------------------------------------
 // Structure used when constructing formatting object trees.
 struct nsFrameItems : public nsFrameList
 {
   // Appends the frame to the end of the list
   void AddChild(nsIFrame* aChild);
 };
 void
 nsFrameItems::AddChild(nsIFrame* aChild)
 {
   NS_PRECONDITION(aChild, "nsFrameItems::AddChild");
   // It'd be really nice if we could just AppendFrames(kPrincipalList, aChild) here,
   // but some of our callers put frames that have different
   // parents (caption, I'm looking at you) on the same framelist, and
   // nsFrameList asserts if you try to do that.
   if (IsEmpty()) {
     SetFrames(aChild);
   }
   else {
     NS_ASSERTION(aChild != mLastChild,
                  "Same frame being added to frame list twice?");
     mLastChild->SetNextSibling(aChild);
     mLastChild = nsLayoutUtils::GetLastSibling(aChild);
   }
 }
 // -----------------------------------------------------------
 // Structure used when constructing formatting object trees. Contains
 // state information needed for absolutely positioned elements
 struct nsAbsoluteItems : nsFrameItems {
   // containing block for absolutely positioned elements
   nsIFrame* containingBlock;
   nsAbsoluteItems(nsIFrame* aContainingBlock);
 #ifdef DEBUG
   // XXXbz Does this need a debug-only assignment operator that nulls out the
   // childList in the nsAbsoluteItems we're copying?  Introducing a difference
   // between debug and non-debug behavior seems bad, so I guess not...
   ~nsAbsoluteItems() {
     NS_ASSERTION(!FirstChild(),
                  "Dangling child list.  Someone forgot to insert it?");
   }
 #endif
   // Appends the frame to the end of the list
   void AddChild(nsIFrame* aChild);
 };
 nsAbsoluteItems::nsAbsoluteItems(nsIFrame* aContainingBlock)
   : containingBlock(aContainingBlock)
 {
 }
 // Additional behavior is that it sets the frame's NS_FRAME_OUT_OF_FLOW flag
 void
 nsAbsoluteItems::AddChild(nsIFrame* aChild)
 {
   NS_ASSERTION(aChild->PresContext()->FrameManager()->
                GetPlaceholderFrameFor(aChild),
                "Child without placeholder being added to nsAbsoluteItems?");
   aChild->AddStateBits(NS_FRAME_OUT_OF_FLOW);
   nsFrameItems::AddChild(aChild);
 }
 // -----------------------------------------------------------
 // Structure for saving the existing state when pushing/poping containing
 // blocks. The destructor restores the state to its previous state
 class MOZ_STACK_CLASS nsFrameConstructorSaveState {
 public:
   typedef nsIFrame::ChildListID ChildListID;
   nsFrameConstructorSaveState();
   ~nsFrameConstructorSaveState();
 private:
   nsAbsoluteItems* mItems;      // pointer to struct whose data we save/restore
   nsAbsoluteItems  mSavedItems; // copy of original data
   // The name of the child list in which our frames would belong
   ChildListID mChildListID;
   nsFrameConstructorState* mState;
   // State used only when we're saving the abs-pos state for a transformed
   // element.
   nsAbsoluteItems mSavedFixedItems;
   bool mSavedFixedPosIsAbsPos;
   friend class nsFrameConstructorState;
 };
 // Structure used to keep track of a list of bindings we need to call
 // AddToAttachedQueue on.  These should be in post-order depth-first
 // flattened tree traversal order.
 struct PendingBinding : public LinkedListElement<PendingBinding>
 {
 #ifdef NS_BUILD_REFCNT_LOGGING
   PendingBinding() {
     MOZ_COUNT_CTOR(PendingBinding);
   }
   ~PendingBinding() {
     MOZ_COUNT_DTOR(PendingBinding);
   }
 #endif
   nsRefPtr<nsXBLBinding> mBinding;
 };
 // Structure used for maintaining state information during the
 // frame construction process
 class MOZ_STACK_CLASS nsFrameConstructorState {
 public:
   typedef nsIFrame::ChildListID ChildListID;
   nsPresContext            *mPresContext;
   nsIPresShell             *mPresShell;
   nsFrameManager           *mFrameManager;
 #ifdef MOZ_XUL
   // Frames destined for the kPopupList.
   nsAbsoluteItems           mPopupItems;
 #endif
   // Containing block information for out-of-flow frames.
   nsAbsoluteItems           mFixedItems;
   nsAbsoluteItems           mAbsoluteItems;
   nsAbsoluteItems           mFloatedItems;
   nsCOMPtr<nsILayoutHistoryState> mFrameState;
   // These bits will be added to the state bits of any frame we construct
   // using this state.
   nsFrameState              mAdditionalStateBits;
   // When working with the -moz-transform property, we want to hook
   // the abs-pos and fixed-pos lists together, since transformed
   // elements are fixed-pos containing blocks.  This flag determines
   // whether or not we want to wire the fixed-pos and abs-pos lists
   // together.
   bool                      mFixedPosIsAbsPos;
   // A boolean to indicate whether we have a "pending" popupgroup.  That is, we
   // have already created the FrameConstructionItem for the root popupgroup but
   // we have not yet created the relevant frame.
   bool                      mHavePendingPopupgroup;
   // If false (which is the default) then call SetPrimaryFrame() as needed
   // during frame construction.  If true, don't make any SetPrimaryFrame()
   // calls, except for generated content which doesn't have a primary frame
   // yet.  The mCreatingExtraFrames == true mode is meant to be used for
   // construction of random "extra" frames for elements via normal frame
   // construction APIs (e.g. replication of things across pages in paginated
   // mode).
   bool                      mCreatingExtraFrames;
   nsCOMArray<nsIContent>    mGeneratedTextNodesWithInitializer;
   TreeMatchContext          mTreeMatchContext;
   // Constructor
   // Use the passed-in history state.
   nsFrameConstructorState(nsIPresShell*          aPresShell,
                           nsIFrame*              aFixedContainingBlock,
                           nsIFrame*              aAbsoluteContainingBlock,
                           nsIFrame*              aFloatContainingBlock,
                           nsILayoutHistoryState* aHistoryState);
   // Get the history state from the pres context's pres shell.
   nsFrameConstructorState(nsIPresShell*          aPresShell,
                           nsIFrame*              aFixedContainingBlock,
                           nsIFrame*              aAbsoluteContainingBlock,
                           nsIFrame*              aFloatContainingBlock);
   ~nsFrameConstructorState();
   // Function to push the existing absolute containing block state and
   // create a new scope. Code that uses this function should get matching
   // logic in GetAbsoluteContainingBlock.
   // Also makes aNewAbsoluteContainingBlock the containing block for
   // fixed-pos elements if necessary.
   // aPositionedFrame is the frame whose style actually makes
   // aNewAbsoluteContainingBlock a containing block. E.g. for a scrollable element
   // aPositionedFrame is the element's primary frame and
   // aNewAbsoluteContainingBlock is the scrolled frame.
   void PushAbsoluteContainingBlock(nsIFrame* aNewAbsoluteContainingBlock,
                                    nsIFrame* aPositionedFrame,
                                    nsFrameConstructorSaveState& aSaveState);
   // Function to push the existing float containing block state and
   // create a new scope. Code that uses this function should get matching
   // logic in GetFloatContainingBlock.
   // Pushing a null float containing block forbids any frames from being
   // floated until a new float containing block is pushed.
   // XXX we should get rid of null float containing blocks and teach the
   // various frame classes to deal with floats instead.
   void PushFloatContainingBlock(nsIFrame* aNewFloatContainingBlock,
                                 nsFrameConstructorSaveState& aSaveState);
   // Function to return the proper geometric parent for a frame with display
   // struct given by aStyleDisplay and parent's frame given by
   // aContentParentFrame.
   nsIFrame* GetGeometricParent(const nsStyleDisplay* aStyleDisplay,
                                nsIFrame* aContentParentFrame) const;
   /**
    * Function to add a new frame to the right frame list.  This MUST be called
    * on frames before their children have been processed if the frames might
    * conceivably be out-of-flow; otherwise cleanup in error cases won't work
    * right.  Also, this MUST be called on frames after they have been
    * initialized.
    * @param aNewFrame the frame to add
    * @param aFrameItems the list to add in-flow frames to
    * @param aContent the content pointer for aNewFrame
    * @param aStyleContext the style context resolved for aContent
    * @param aParentFrame the parent frame for the content if it were in-flow
    * @param aCanBePositioned pass false if the frame isn't allowed to be
    *        positioned
    * @param aCanBeFloated pass false if the frame isn't allowed to be
    *        floated
    * @param aIsOutOfFlowPopup pass true if the frame is an out-of-flow popup
    *        (XUL-only)
    */
   void AddChild(nsIFrame* aNewFrame,
                 nsFrameItems& aFrameItems,
                 nsIContent* aContent,
                 nsStyleContext* aStyleContext,
                 nsIFrame* aParentFrame,
                 bool aCanBePositioned = true,
                 bool aCanBeFloated = true,
                 bool aIsOutOfFlowPopup = false,
                 bool aInsertAfter = false,
                 nsIFrame* aInsertAfterFrame = nullptr);
   /**
    * Function to return the fixed-pos element list.  Normally this will just hand back the
    * fixed-pos element list, but in case we're dealing with a transformed element that's
    * acting as an abs-pos and fixed-pos container, we'll hand back the abs-pos list.  Callers should
    * use this function if they want to get the list acting as the fixed-pos item parent.
    */
   nsAbsoluteItems& GetFixedItems()
   {
     return mFixedPosIsAbsPos ? mAbsoluteItems : mFixedItems;
   }
   const nsAbsoluteItems& GetFixedItems() const
   {
     return mFixedPosIsAbsPos ? mAbsoluteItems : mFixedItems;
   }
   /**
    * class to automatically push and pop a pending binding in the frame
    * constructor state.  See nsCSSFrameConstructor::FrameConstructionItem
    * mPendingBinding documentation.
    */
   class PendingBindingAutoPusher;
   friend class PendingBindingAutoPusher;
   class MOZ_STACK_CLASS PendingBindingAutoPusher {
   public:
     PendingBindingAutoPusher(nsFrameConstructorState& aState,
                              PendingBinding* aPendingBinding) :
       mState(aState),
       mPendingBinding(aState.mCurrentPendingBindingInsertionPoint)
         {
           if (aPendingBinding) {
             aState.mCurrentPendingBindingInsertionPoint = aPendingBinding;
           }
         }
     ~PendingBindingAutoPusher()
       {
         mState.mCurrentPendingBindingInsertionPoint = mPendingBinding;
       }
   private:
     nsFrameConstructorState& mState;
     PendingBinding* mPendingBinding;
   };
   /**
    * Add a new pending binding to the list
    */
   void AddPendingBinding(PendingBinding* aPendingBinding) {
     if (mCurrentPendingBindingInsertionPoint) {
       mCurrentPendingBindingInsertionPoint->setPrevious(aPendingBinding);
     } else {
       mPendingBindings.insertBack(aPendingBinding);
     }
   }
 protected:
   friend class nsFrameConstructorSaveState;
   /**
    * ProcessFrameInsertions takes the frames in aFrameItems and adds them as
    * kids to the aChildListID child list of |aFrameItems.containingBlock|.
    */
   void ProcessFrameInsertions(nsAbsoluteItems& aFrameItems,
                               ChildListID aChildListID);
   // Our list of all pending bindings.  When we're done, we need to call
   // AddToAttachedQueue on all of them, in order.
   LinkedList<PendingBinding> mPendingBindings;
   PendingBinding* mCurrentPendingBindingInsertionPoint;
 };
 nsFrameConstructorState::nsFrameConstructorState(nsIPresShell*          aPresShell,
                                                  nsIFrame*              aFixedContainingBlock,
                                                  nsIFrame*              aAbsoluteContainingBlock,
                                                  nsIFrame*              aFloatContainingBlock,
                                                  nsILayoutHistoryState* aHistoryState)
   : mPresContext(aPresShell->GetPresContext()),
     mPresShell(aPresShell),
     mFrameManager(aPresShell->FrameManager()),
 #ifdef MOZ_XUL
     mPopupItems(nullptr),
 #endif
     mFixedItems(aFixedContainingBlock),
     mAbsoluteItems(aAbsoluteContainingBlock),
     mFloatedItems(aFloatContainingBlock),
     // See PushAbsoluteContaningBlock below
     mFrameState(aHistoryState),
     mAdditionalStateBits(nsFrameState(0)),
     // If the fixed-pos containing block is equal to the abs-pos containing
     // block, use the abs-pos containing block's abs-pos list for fixed-pos
 	// frames.
     mFixedPosIsAbsPos(aFixedContainingBlock == aAbsoluteContainingBlock),
     mHavePendingPopupgroup(false),
     mCreatingExtraFrames(false),
     mTreeMatchContext(true, nsRuleWalker::eRelevantLinkUnvisited,
                       aPresShell->GetDocument()),
     mCurrentPendingBindingInsertionPoint(nullptr)
 {
 #ifdef MOZ_XUL
   nsIRootBox* rootBox = nsIRootBox::GetRootBox(aPresShell);
   if (rootBox) {
     mPopupItems.containingBlock = rootBox->GetPopupSetFrame();
   }
 #endif
   MOZ_COUNT_CTOR(nsFrameConstructorState);
 }
 nsFrameConstructorState::nsFrameConstructorState(nsIPresShell* aPresShell,
                                                  nsIFrame*     aFixedContainingBlock,
                                                  nsIFrame*     aAbsoluteContainingBlock,
                                                  nsIFrame*     aFloatContainingBlock)
   : mPresContext(aPresShell->GetPresContext()),
     mPresShell(aPresShell),
     mFrameManager(aPresShell->FrameManager()),
 #ifdef MOZ_XUL
     mPopupItems(nullptr),
 #endif
     mFixedItems(aFixedContainingBlock),
     mAbsoluteItems(aAbsoluteContainingBlock),
     mFloatedItems(aFloatContainingBlock),
     // See PushAbsoluteContaningBlock below
     mAdditionalStateBits(nsFrameState(0)),
     // If the fixed-pos containing block is equal to the abs-pos containing
     // block, use the abs-pos containing block's abs-pos list for fixed-pos
 	// frames.
     mFixedPosIsAbsPos(aFixedContainingBlock == aAbsoluteContainingBlock),
     mHavePendingPopupgroup(false),
     mCreatingExtraFrames(false),
     mTreeMatchContext(true, nsRuleWalker::eRelevantLinkUnvisited,
                       aPresShell->GetDocument()),
     mCurrentPendingBindingInsertionPoint(nullptr)
 {
 #ifdef MOZ_XUL
   nsIRootBox* rootBox = nsIRootBox::GetRootBox(aPresShell);
   if (rootBox) {
     mPopupItems.containingBlock = rootBox->GetPopupSetFrame();
   }
 #endif
   MOZ_COUNT_CTOR(nsFrameConstructorState);
   mFrameState = aPresShell->GetDocument()->GetLayoutHistoryState();
 }
 nsFrameConstructorState::~nsFrameConstructorState()
 {
   // Frame order comparison functions only work properly when the placeholders
   // have been inserted into the frame tree. So for example if we have a new float
   // containing the placeholder for a new abs-pos frame, and we process the abs-pos
   // insertion first, then we won't be able to find the right place to insert in
   // in the abs-pos list. So put floats in first, because they can contain placeholders
   // for abs-pos and fixed-pos items whose containing blocks are outside the floats.
   // Then put abs-pos frames in, because they can contain placeholders for fixed-pos
   // items whose containing block is outside the abs-pos frames.
   MOZ_COUNT_DTOR(nsFrameConstructorState);
   ProcessFrameInsertions(mFloatedItems, nsIFrame::kFloatList);
   ProcessFrameInsertions(mAbsoluteItems, nsIFrame::kAbsoluteList);
   ProcessFrameInsertions(mFixedItems, nsIFrame::kFixedList);
 #ifdef MOZ_XUL
   ProcessFrameInsertions(mPopupItems, nsIFrame::kPopupList);
 #endif
   for (int32_t i = mGeneratedTextNodesWithInitializer.Count() - 1; i >= 0; --i) {
     mGeneratedTextNodesWithInitializer[i]->
       DeleteProperty(nsGkAtoms::genConInitializerProperty);
   }
   if (!mPendingBindings.isEmpty()) {
     nsBindingManager* bindingManager = mPresShell->GetDocument()->BindingManager();
     do {
       nsAutoPtr<PendingBinding> pendingBinding;
       pendingBinding = mPendingBindings.popFirst();
       bindingManager->AddToAttachedQueue(pendingBinding->mBinding);
     } while (!mPendingBindings.isEmpty());
     mCurrentPendingBindingInsertionPoint = nullptr;
   }
 }
 static nsIFrame*
 AdjustAbsoluteContainingBlock(nsIFrame* aContainingBlockIn)
 {
   if (!aContainingBlockIn) {
     return nullptr;
   }
   // Always use the container's first continuation. (Inline frames can have
   // non-fluid bidi continuations...)
   return aContainingBlockIn->FirstContinuation();
 }
 void
 nsFrameConstructorState::PushAbsoluteContainingBlock(nsIFrame* aNewAbsoluteContainingBlock,
                                                      nsIFrame* aPositionedFrame,
                                                      nsFrameConstructorSaveState& aSaveState)
 {
   aSaveState.mItems = &mAbsoluteItems;
   aSaveState.mSavedItems = mAbsoluteItems;
   aSaveState.mChildListID = nsIFrame::kAbsoluteList;
   aSaveState.mState = this;
   aSaveState.mSavedFixedPosIsAbsPos = mFixedPosIsAbsPos;
   if (mFixedPosIsAbsPos) {
     // Since we're going to replace mAbsoluteItems, we need to save it into
     // mFixedItems now (and save the current value of mFixedItems).
     aSaveState.mSavedFixedItems = mFixedItems;
     mFixedItems = mAbsoluteItems;
   }
   mAbsoluteItems =
     nsAbsoluteItems(AdjustAbsoluteContainingBlock(aNewAbsoluteContainingBlock));
   /* See if we're wiring the fixed-pos and abs-pos lists together.  This happens iff
    * we're a transformed element.
    */
   mFixedPosIsAbsPos = aPositionedFrame &&
       (aPositionedFrame->StyleDisplay()->HasTransform(aPositionedFrame) ||
        aPositionedFrame->StyleDisplay()->HasPerspectiveStyle());
   if (aNewAbsoluteContainingBlock) {
     aNewAbsoluteContainingBlock->MarkAsAbsoluteContainingBlock();
   }
 }
 void
 nsFrameConstructorState::PushFloatContainingBlock(nsIFrame* aNewFloatContainingBlock,
                                                   nsFrameConstructorSaveState& aSaveState)
 {
   NS_PRECONDITION(!aNewFloatContainingBlock ||
                   aNewFloatContainingBlock->IsFloatContainingBlock(),
                   "Please push a real float containing block!");
   NS_ASSERTION(!aNewFloatContainingBlock ||
                !ShouldSuppressFloatingOfDescendants(aNewFloatContainingBlock),
                "We should not push a frame that is supposed to _suppress_ "
                "floats as a float containing block!");
   aSaveState.mItems = &mFloatedItems;
   aSaveState.mSavedItems = mFloatedItems;
   aSaveState.mChildListID = nsIFrame::kFloatList;
   aSaveState.mState = this;
   mFloatedItems = nsAbsoluteItems(aNewFloatContainingBlock);
 }
 nsIFrame*
 nsFrameConstructorState::GetGeometricParent(const nsStyleDisplay* aStyleDisplay,
                                             nsIFrame* aContentParentFrame) const
 {
   NS_PRECONDITION(aStyleDisplay, "Must have display struct!");
   // If there is no container for a fixed, absolute, or floating root
   // frame, we will ignore the positioning.  This hack is originally
   // brought to you by the letter T: tables, since other roots don't
   // even call into this code.  See bug 178855.
   //
   // XXX Disabling positioning in this case is a hack.  If one was so inclined,
   // one could support this either by (1) inserting a dummy block between the
   // table and the canvas or (2) teaching the canvas how to reflow positioned
   // elements. (1) has the usual problems when multiple frames share the same
   // content (notice all the special cases in this file dealing with inner
   // tables and outer tables which share the same content). (2) requires some
   // work and possible factoring.
   //
   // XXXbz couldn't we just force position to "static" on roots and
   // float to "none"?  That's OK per CSS 2.1, as far as I can tell.
   if (aContentParentFrame && aContentParentFrame->IsSVGText()) {
     return aContentParentFrame;
   }
   if (aStyleDisplay->IsFloatingStyle() && mFloatedItems.containingBlock) {
     NS_ASSERTION(!aStyleDisplay->IsAbsolutelyPositionedStyle(),
                  "Absolutely positioned _and_ floating?");
     return mFloatedItems.containingBlock;
   }
   if (aStyleDisplay->mPosition == NS_STYLE_POSITION_ABSOLUTE &&
       mAbsoluteItems.containingBlock) {
     return mAbsoluteItems.containingBlock;
   }
   if (aStyleDisplay->mPosition == NS_STYLE_POSITION_FIXED &&
       GetFixedItems().containingBlock) {
     return GetFixedItems().containingBlock;
   }
   return aContentParentFrame;
 }
 void
 nsFrameConstructorState::AddChild(nsIFrame* aNewFrame,
                                   nsFrameItems& aFrameItems,
                                   nsIContent* aContent,
                                   nsStyleContext* aStyleContext,
                                   nsIFrame* aParentFrame,
                                   bool aCanBePositioned,
                                   bool aCanBeFloated,
                                   bool aIsOutOfFlowPopup,
                                   bool aInsertAfter,
                                   nsIFrame* aInsertAfterFrame)
 {
   NS_PRECONDITION(!aNewFrame->GetNextSibling(), "Shouldn't happen");
   const nsStyleDisplay* disp = aNewFrame->StyleDisplay();
   // The comments in GetGeometricParent regarding root table frames
   // all apply here, unfortunately.
   bool needPlaceholder = false;
   nsFrameState placeholderType;
   nsFrameItems* frameItems = &aFrameItems;
 #ifdef MOZ_XUL
   if (MOZ_UNLIKELY(aIsOutOfFlowPopup)) {
       NS_ASSERTION(aNewFrame->GetParent() == mPopupItems.containingBlock,
                    "Popup whose parent is not the popup containing block?");
       NS_ASSERTION(mPopupItems.containingBlock, "Must have a popup set frame!");
       needPlaceholder = true;
       frameItems = &mPopupItems;
       placeholderType = PLACEHOLDER_FOR_POPUP;
   }
   else
 #endif // MOZ_XUL
   if (aCanBeFloated && aNewFrame->IsFloating() &&
       mFloatedItems.containingBlock) {
     NS_ASSERTION(aNewFrame->GetParent() == mFloatedItems.containingBlock,
                  "Float whose parent is not the float containing block?");
     needPlaceholder = true;
     frameItems = &mFloatedItems;
     placeholderType = PLACEHOLDER_FOR_FLOAT;
   }
   else if (aCanBePositioned) {
     if (disp->mPosition == NS_STYLE_POSITION_ABSOLUTE &&
         mAbsoluteItems.containingBlock) {
       NS_ASSERTION(aNewFrame->GetParent() == mAbsoluteItems.containingBlock,
                    "Abs pos whose parent is not the abs pos containing block?");
       needPlaceholder = true;
       frameItems = &mAbsoluteItems;
       placeholderType = PLACEHOLDER_FOR_ABSPOS;
     }
     if (disp->mPosition == NS_STYLE_POSITION_FIXED &&
         GetFixedItems().containingBlock) {
       NS_ASSERTION(aNewFrame->GetParent() == GetFixedItems().containingBlock,
                    "Fixed pos whose parent is not the fixed pos containing block?");
       needPlaceholder = true;
       frameItems = &GetFixedItems();
       placeholderType = PLACEHOLDER_FOR_FIXEDPOS;
     }
   }
   if (needPlaceholder) {
     NS_ASSERTION(frameItems != &aFrameItems,
                  "Putting frame in-flow _and_ want a placeholder?");
     nsIFrame* placeholderFrame =
       nsCSSFrameConstructor::CreatePlaceholderFrameFor(mPresShell,
                                                        aContent,
                                                        aNewFrame,
                                                        aStyleContext,
                                                        aParentFrame,
                                                        nullptr,
                                                        placeholderType);
     placeholderFrame->AddStateBits(mAdditionalStateBits);
     // Add the placeholder frame to the flow
     aFrameItems.AddChild(placeholderFrame);
   }
 #ifdef DEBUG
   else {
     NS_ASSERTION(aNewFrame->GetParent() == aParentFrame,
                  "In-flow frame has wrong parent");
   }
 #endif
   if (aInsertAfter) {
     frameItems->InsertFrame(nullptr, aInsertAfterFrame, aNewFrame);
   } else {
     frameItems->AddChild(aNewFrame);
   }
 }
 void
 nsFrameConstructorState::ProcessFrameInsertions(nsAbsoluteItems& aFrameItems,
                                                 ChildListID aChildListID)
 {
 #define NS_NONXUL_LIST_TEST (&aFrameItems == &mFloatedItems &&            \
                              aChildListID == nsIFrame::kFloatList)    ||  \
                             (&aFrameItems == &mAbsoluteItems &&           \
                              aChildListID == nsIFrame::kAbsoluteList) ||  \
                             (&aFrameItems == &mFixedItems &&              \
                              aChildListID == nsIFrame::kFixedList)
 #ifdef MOZ_XUL
   NS_PRECONDITION(NS_NONXUL_LIST_TEST ||
                   (&aFrameItems == &mPopupItems &&
                    aChildListID == nsIFrame::kPopupList),
                   "Unexpected aFrameItems/aChildListID combination");
 #else
   NS_PRECONDITION(NS_NONXUL_LIST_TEST,
                   "Unexpected aFrameItems/aChildListID combination");
 #endif
   if (aFrameItems.IsEmpty()) {
     return;
   }
   nsIFrame* containingBlock = aFrameItems.containingBlock;
   NS_ASSERTION(containingBlock,
                "Child list without containing block?");
   if (aChildListID == nsIFrame::kFixedList) {
     // Put this frame on the transformed-frame's abs-pos list instead, if
     // it has abs-pos children instead of fixed-pos children.
     aChildListID = containingBlock->GetAbsoluteListID();
   }
   // Insert the frames hanging out in aItems.  We can use SetInitialChildList()
   // if the containing block hasn't been reflowed yet (so NS_FRAME_FIRST_REFLOW
   // is set) and doesn't have any frames in the aChildListID child list yet.
   const nsFrameList& childList = containingBlock->GetChildList(aChildListID);
   DebugOnly<nsresult> rv = NS_OK;
   if (childList.IsEmpty() &&
       (containingBlock->GetStateBits() & NS_FRAME_FIRST_REFLOW)) {
     // If we're injecting absolutely positioned frames, inject them on the
     // absolute containing block
     if (aChildListID == containingBlock->GetAbsoluteListID()) {
       rv = containingBlock->GetAbsoluteContainingBlock()->
            SetInitialChildList(containingBlock, aChildListID, aFrameItems);
     } else {
       rv = containingBlock->SetInitialChildList(aChildListID, aFrameItems);
     }
   } else {
     // Note that whether the frame construction context is doing an append or
     // not is not helpful here, since it could be appending to some frame in
     // the middle of the document, which means we're not necessarily
     // appending to the children of the containing block.
     //
     // We need to make sure the 'append to the end of document' case is fast.
     // So first test the last child of the containing block
     nsIFrame* lastChild = childList.LastChild();
     // CompareTreePosition uses placeholder hierarchy for out of flow frames,
     // so this will make out-of-flows respect the ordering of placeholders,
     // which is great because it takes care of anonymous content.
     nsIFrame* firstNewFrame = aFrameItems.FirstChild();
     // Cache the ancestor chain so that we can reuse it if needed.
     nsAutoTArray<nsIFrame*, 20> firstNewFrameAncestors;
     nsIFrame* notCommonAncestor = nullptr;
     if (lastChild) {
       notCommonAncestor = nsLayoutUtils::FillAncestors(firstNewFrame,
                                                        containingBlock,
                                                        &firstNewFrameAncestors);
     }
     if (!lastChild ||
         nsLayoutUtils::CompareTreePosition(lastChild, firstNewFrame,
                                            firstNewFrameAncestors,
                                            notCommonAncestor ?
                                              containingBlock : nullptr) < 0) {
       // no lastChild, or lastChild comes before the new children, so just append
       rv = mFrameManager->AppendFrames(containingBlock, aChildListID, aFrameItems);
     } else {
       // Try the other children. First collect them to an array so that a
       // reasonable fast binary search can be used to find the insertion point.
       nsAutoTArray<nsIFrame*, 128> children;
       for (nsIFrame* f = childList.FirstChild(); f != lastChild;
            f = f->GetNextSibling()) {
         children.AppendElement(f);
       }
       nsIFrame* insertionPoint = nullptr;
       int32_t imin = 0;
       int32_t max = children.Length();
       while (max > imin) {
         int32_t imid = imin + ((max - imin) / 2);
         nsIFrame* f = children[imid];
         int32_t compare =
           nsLayoutUtils::CompareTreePosition(f, firstNewFrame, firstNewFrameAncestors,
                                              notCommonAncestor ? containingBlock : nullptr);
         if (compare > 0) {
           // f is after the new frame.
           max = imid;
           insertionPoint = imid > 0 ? children[imid - 1] : nullptr;
         } else if (compare < 0) {
           // f is before the new frame.
           imin = imid + 1;
           insertionPoint = f;
         } else {
           // This is for the old behavior. Should be removed once it is
           // guaranteed that CompareTreePosition can't return 0!
           // See bug 928645.
           NS_WARNING("Something odd happening???");
           insertionPoint = nullptr;
           for (uint32_t i = 0; i < children.Length(); ++i) {
             nsIFrame* f = children[i];
             if (nsLayoutUtils::CompareTreePosition(f, firstNewFrame,
                                                    firstNewFrameAncestors,
                                                    notCommonAncestor ?
                                                      containingBlock : nullptr) > 0) {
               break;
             }
             insertionPoint = f;
           }
           break;
         }
       }
       rv = mFrameManager->InsertFrames(containingBlock, aChildListID,
                                        insertionPoint, aFrameItems);
     }
   }
   NS_POSTCONDITION(aFrameItems.IsEmpty(), "How did that happen?");
   // XXXbz And if NS_FAILED(rv), what?  I guess we need to clean up the list
   // and deal with all the placeholders... but what if the placeholders aren't
   // in the document yet?  Could that happen?
   NS_ASSERTION(NS_SUCCEEDED(rv), "Frames getting lost!");
 }
 nsFrameConstructorSaveState::nsFrameConstructorSaveState()
   : mItems(nullptr),
     mSavedItems(nullptr),
     mChildListID(kPrincipalList),
     mState(nullptr),
     mSavedFixedItems(nullptr),
     mSavedFixedPosIsAbsPos(false)
 {
 }
 nsFrameConstructorSaveState::~nsFrameConstructorSaveState()
 {
   // Restore the state
   if (mItems) {
     NS_ASSERTION(mState, "Can't have mItems set without having a state!");
     mState->ProcessFrameInsertions(*mItems, mChildListID);
     *mItems = mSavedItems;
 #ifdef DEBUG
     // We've transferred the child list, so drop the pointer we held to it.
     // Note that this only matters for the assert in ~nsAbsoluteItems.
     mSavedItems.Clear();
 #endif
     if (mItems == &mState->mAbsoluteItems) {
       mState->mFixedPosIsAbsPos = mSavedFixedPosIsAbsPos;
       if (mSavedFixedPosIsAbsPos) {
         // mAbsoluteItems was moved to mFixedItems, so move mFixedItems back
         // and repair the old mFixedItems now.
         mState->mAbsoluteItems = mState->mFixedItems;
         mState->mFixedItems = mSavedFixedItems;
 #ifdef DEBUG
         mSavedFixedItems.Clear();
 #endif
       }
     }
     NS_ASSERTION(!mItems->LastChild() || !mItems->LastChild()->GetNextSibling(),
                  "Something corrupted our list");
   }
 }
 static
 bool IsBorderCollapse(nsIFrame* aFrame)
 {
   for (nsIFrame* frame = aFrame; frame; frame = frame->GetParent()) {
     if (nsGkAtoms::tableFrame == frame->GetType()) {
       return ((nsTableFrame*)frame)->IsBorderCollapse();
     }
   }
   NS_ASSERTION(false, "program error");
   return false;
 }
 /**
  * Moves aFrameList from aOldParent to aNewParent.  This updates the parent
  * pointer of the frames in the list, and reparents their views as needed.
  * nsFrame::SetParent sets the NS_FRAME_HAS_VIEW bit on aNewParent and its
  * ancestors as needed. Then it sets the list as the initial child list
  * on aNewParent, unless aNewParent either already has kids or has been
  * reflowed; in that case it appends the new frames.  Note that this
  * method differs from ReparentFrames in that it doesn't change the kids'
  * style contexts.
  */
 // XXXbz Since this is only used for {ib} splits, could we just copy the view
 // bits from aOldParent to aNewParent and then use the
 // nsFrameList::ApplySetParent?  That would still leave us doing two passes
 // over the list, of course; if we really wanted to we could factor out the
 // relevant part of ReparentFrameViewList, I suppose...  Or just get rid of
 // views, which would make most of this function go away.
 static void
 MoveChildrenTo(nsPresContext* aPresContext,
                nsIFrame* aOldParent,
                nsIFrame* aNewParent,
                nsFrameList& aFrameList)
 {
   bool sameGrandParent = aOldParent->GetParent() == aNewParent->GetParent();
   if (aNewParent->HasView() || aOldParent->HasView() || !sameGrandParent) {
     // Move the frames into the new view
     nsContainerFrame::ReparentFrameViewList(aFrameList, aOldParent, aNewParent);
   }
   for (nsFrameList::Enumerator e(aFrameList); !e.AtEnd(); e.Next()) {
     e.get()->SetParent(aNewParent);
   }
   if (aNewParent->PrincipalChildList().IsEmpty() &&
       (aNewParent->GetStateBits() & NS_FRAME_FIRST_REFLOW)) {
     aNewParent->SetInitialChildList(kPrincipalList, aFrameList);
   } else {
     aNewParent->AppendFrames(kPrincipalList, aFrameList);
   }
 }
 //----------------------------------------------------------------------
 nsCSSFrameConstructor::nsCSSFrameConstructor(nsIDocument *aDocument,
                                              nsIPresShell *aPresShell,
                                              nsStyleSet* aStyleSet)
   : nsFrameManager(aPresShell, aStyleSet)
   , mDocument(aDocument)
   , mRootElementFrame(nullptr)
   , mRootElementStyleFrame(nullptr)
   , mFixedContainingBlock(nullptr)
   , mDocElementContainingBlock(nullptr)
   , mGfxScrollFrame(nullptr)
   , mPageSequenceFrame(nullptr)
   , mCurrentDepth(0)
   , mUpdateCount(0)
   , mQuotesDirty(false)
   , mCountersDirty(false)
   , mIsDestroyingFrameTree(false)
   , mHasRootAbsPosContainingBlock(false)
   , mAlwaysCreateFramesForIgnorableWhitespace(false)
 {
 #ifdef DEBUG
   static bool gFirstTime = true;
   if (gFirstTime) {
     gFirstTime = false;
     char* flags = PR_GetEnv("GECKO_FRAMECTOR_DEBUG_FLAGS");
     if (flags) {
       bool error = false;
       for (;;) {
         char* comma = PL_strchr(flags, ',');
         if (comma)
           *comma = '\0';
         bool found = false;
         FrameCtorDebugFlags* flag = gFlags;
         FrameCtorDebugFlags* limit = gFlags + NUM_DEBUG_FLAGS;
         while (flag < limit) {
           if (PL_strcasecmp(flag->name, flags) == 0) {
             *(flag->on) = true;
             printf("nsCSSFrameConstructor: setting %s debug flag on\n", flag->name);
             found = true;
             break;
           }
           ++flag;
         }
         if (! found)
           error = true;
         if (! comma)
           break;
         *comma = ',';
         flags = comma + 1;
       }
       if (error) {
         printf("Here are the available GECKO_FRAMECTOR_DEBUG_FLAGS:\n");
         FrameCtorDebugFlags* flag = gFlags;
         FrameCtorDebugFlags* limit = gFlags + NUM_DEBUG_FLAGS;
         while (flag < limit) {
           printf("  %s\n", flag->name);
           ++flag;
         }
         printf("Note: GECKO_FRAMECTOR_DEBUG_FLAGS is a comma separated list of flag\n");
         printf("names (no whitespace)\n");
       }
     }
   }
 #endif
 }
 void
 nsCSSFrameConstructor::NotifyDestroyingFrame(nsIFrame* aFrame)
 {
   NS_PRECONDITION(mUpdateCount != 0,
                   "Should be in an update while destroying frames");
   if (aFrame->GetStateBits() & NS_FRAME_GENERATED_CONTENT) {
     if (mQuoteList.DestroyNodesFor(aFrame))
       QuotesDirty();
   }
   if (mCounterManager.DestroyNodesFor(aFrame)) {
     // Technically we don't need to update anything if we destroyed only
     // USE nodes.  However, this is unlikely to happen in the real world
     // since USE nodes generally go along with INCREMENT nodes.
     CountersDirty();
   }
   RestyleManager()->NotifyDestroyingFrame(aFrame);
   nsFrameManager::NotifyDestroyingFrame(aFrame);
 }
 struct nsGenConInitializer {
   nsAutoPtr<nsGenConNode> mNode;
   nsGenConList*           mList;
   void (nsCSSFrameConstructor::*mDirtyAll)();
   nsGenConInitializer(nsGenConNode* aNode, nsGenConList* aList,
                       void (nsCSSFrameConstructor::*aDirtyAll)())
     : mNode(aNode), mList(aList), mDirtyAll(aDirtyAll) {}
 };
 already_AddRefed<nsIContent>
 nsCSSFrameConstructor::CreateGenConTextNode(nsFrameConstructorState& aState,
                                             const nsString& aString,
                                             nsCOMPtr<nsIDOMCharacterData>* aText,
                                             nsGenConInitializer* aInitializer)
 {
   nsRefPtr<nsTextNode> content = new nsTextNode(mDocument->NodeInfoManager());
   content->SetText(aString, false);
   if (aText) {
     *aText = content;
   }
   if (aInitializer) {
     content->SetProperty(nsGkAtoms::genConInitializerProperty, aInitializer,
                          nsINode::DeleteProperty<nsGenConInitializer>);
     aState.mGeneratedTextNodesWithInitializer.AppendObject(content);
   }
   return content.forget();
 }
 already_AddRefed<nsIContent>
 nsCSSFrameConstructor::CreateGeneratedContent(nsFrameConstructorState& aState,
                                               nsIContent*     aParentContent,
                                               nsStyleContext* aStyleContext,
                                               uint32_t        aContentIndex)
 {
   // Get the content value
   const nsStyleContentData &data =
     aStyleContext->StyleContent()->ContentAt(aContentIndex);
   nsStyleContentType type = data.mType;
   if (eStyleContentType_Image == type) {
     if (!data.mContent.mImage) {
       // CSS had something specified that couldn't be converted to an
       // image object
       return nullptr;
     }
     // Create an image content object and pass it the image request.
     // XXX Check if it's an image type we can handle...
     nsCOMPtr<nsINodeInfo> nodeInfo;
     nodeInfo = mDocument->NodeInfoManager()->
       GetNodeInfo(nsGkAtoms::mozgeneratedcontentimage, nullptr,
                   kNameSpaceID_XHTML, nsIDOMNode::ELEMENT_NODE);
     nsCOMPtr<nsIContent> content;
     NS_NewGenConImageContent(getter_AddRefs(content), nodeInfo.forget(),
                              data.mContent.mImage);
     return content.forget();
   }
   switch (type) {
   case eStyleContentType_String:
     return CreateGenConTextNode(aState,
                                 nsDependentString(data.mContent.mString),
                                 nullptr, nullptr);
   case eStyleContentType_Attr:
     {
       nsCOMPtr<nsIAtom> attrName;
       int32_t attrNameSpace = kNameSpaceID_None;
       nsAutoString contentString(data.mContent.mString);
       int32_t barIndex = contentString.FindChar('|'); // CSS namespace delimiter
       if (-1 != barIndex) {
         nsAutoString  nameSpaceVal;
         contentString.Left(nameSpaceVal, barIndex);
         nsresult error;
         attrNameSpace = nameSpaceVal.ToInteger(&error);
         contentString.Cut(0, barIndex + 1);
         if (contentString.Length()) {
           if (mDocument->IsHTML() && aParentContent->IsHTML()) {
             ToLowerCase(contentString);
           }
           attrName = do_GetAtom(contentString);
         }
       }
       else {
         if (mDocument->IsHTML() && aParentContent->IsHTML()) {
           ToLowerCase(contentString);
         }
         attrName = do_GetAtom(contentString);
       }
       if (!attrName) {
         return nullptr;
       }
       nsCOMPtr<nsIContent> content;
       NS_NewAttributeContent(mDocument->NodeInfoManager(),
                              attrNameSpace, attrName, getter_AddRefs(content));
       return content.forget();
     }
   case eStyleContentType_Counter:
   case eStyleContentType_Counters:
     {
       nsCSSValue::Array* counters = data.mContent.mCounters;
       nsCounterList* counterList = mCounterManager.CounterListFor(
           nsDependentString(counters->Item(0).GetStringBufferValue()));
       if (!counterList)
         return nullptr;
       nsCounterUseNode* node =
         new nsCounterUseNode(counters, aContentIndex,
                              type == eStyleContentType_Counters);
       nsGenConInitializer* initializer =
         new nsGenConInitializer(node, counterList,
                                 &nsCSSFrameConstructor::CountersDirty);
       return CreateGenConTextNode(aState, EmptyString(), &node->mText,
                                   initializer);
     }
   case eStyleContentType_Image:
     NS_NOTREACHED("handled by if above");
     return nullptr;
   case eStyleContentType_OpenQuote:
   case eStyleContentType_CloseQuote:
   case eStyleContentType_NoOpenQuote:
   case eStyleContentType_NoCloseQuote:
     {
       nsQuoteNode* node =
         new nsQuoteNode(type, aContentIndex);
       nsGenConInitializer* initializer =
         new nsGenConInitializer(node, &mQuoteList,
                                 &nsCSSFrameConstructor::QuotesDirty);
       return CreateGenConTextNode(aState, EmptyString(), &node->mText,
                                   initializer);
     }
   case eStyleContentType_AltContent:
     {
       // Use the "alt" attribute; if that fails and the node is an HTML
       // <input>, try the value attribute and then fall back to some default
       // localized text we have.
       // XXX what if the 'alt' attribute is added later, how will we
       // detect that and do the right thing here?
       if (aParentContent->HasAttr(kNameSpaceID_None, nsGkAtoms::alt)) {
         nsCOMPtr<nsIContent> content;
         NS_NewAttributeContent(mDocument->NodeInfoManager(),
                                kNameSpaceID_None, nsGkAtoms::alt, getter_AddRefs(content));
         return content.forget();
       }
       if (aParentContent->IsHTML() &&
           aParentContent->NodeInfo()->Equals(nsGkAtoms::input)) {
         if (aParentContent->HasAttr(kNameSpaceID_None, nsGkAtoms::value)) {
           nsCOMPtr<nsIContent> content;
           NS_NewAttributeContent(mDocument->NodeInfoManager(),
                                  kNameSpaceID_None, nsGkAtoms::value, getter_AddRefs(content));
           return content.forget();
         }
         nsXPIDLString temp;
         nsContentUtils::GetLocalizedString(nsContentUtils::eFORMS_PROPERTIES,
                                            "Submit", temp);
         return CreateGenConTextNode(aState, temp, nullptr, nullptr);
       }
       break;
     }
   case eStyleContentType_Uninitialized:
     NS_NOTREACHED("uninitialized content type");
     return nullptr;
   } // switch
   return nullptr;
 }
 /*
  * aParentFrame - the frame that should be the parent of the generated
  *   content.  This is the frame for the corresponding content node,
  *   which must not be a leaf frame.
  *
  * Any items created are added to aItems.
  *
  * We create an XML element (tag _moz_generated_content_before or
  * _moz_generated_content_after) representing the pseudoelement. We
  * create a DOM node for each 'content' item and make those nodes the
  * children of the XML element. Then we create a frame subtree for
  * the XML element as if it were a regular child of
  * aParentFrame/aParentContent, giving the XML element the ::before or
  * ::after style.
  */
 void
 nsCSSFrameConstructor::CreateGeneratedContentItem(nsFrameConstructorState& aState,
                                                   nsIFrame*        aParentFrame,
                                                   nsIContent*      aParentContent,
                                                   nsStyleContext*  aStyleContext,
                                                   nsCSSPseudoElements::Type aPseudoElement,
                                                   FrameConstructionItemList& aItems)
 {
   // XXXbz is this ever true?
   if (!aParentContent->IsElement()) {
     NS_ERROR("Bogus generated content parent");
     return;
   }
   nsStyleSet *styleSet = mPresShell->StyleSet();
   // Probe for the existence of the pseudo-element
   nsRefPtr<nsStyleContext> pseudoStyleContext;
   pseudoStyleContext =
     styleSet->ProbePseudoElementStyle(aParentContent->AsElement(),
                                       aPseudoElement,
                                       aStyleContext,
                                       aState.mTreeMatchContext);
   if (!pseudoStyleContext)
     return;
   // |ProbePseudoStyleFor| checked the 'display' property and the
   // |ContentCount()| of the 'content' property for us.
   nsCOMPtr<nsINodeInfo> nodeInfo;
   nsIAtom* elemName = aPseudoElement == nsCSSPseudoElements::ePseudo_before ?
     nsGkAtoms::mozgeneratedcontentbefore : nsGkAtoms::mozgeneratedcontentafter;
   nodeInfo = mDocument->NodeInfoManager()->GetNodeInfo(elemName, nullptr,
                                                        kNameSpaceID_None,
                                                        nsIDOMNode::ELEMENT_NODE);
   nsCOMPtr<Element> container;
   nsresult rv = NS_NewXMLElement(getter_AddRefs(container), nodeInfo.forget());
   if (NS_FAILED(rv))
     return;
   container->SetIsNativeAnonymousRoot();
   rv = container->BindToTree(mDocument, aParentContent, aParentContent, true);
   if (NS_FAILED(rv)) {
     container->UnbindFromTree();
     return;
   }
   uint32_t contentCount = pseudoStyleContext->StyleContent()->ContentCount();
   for (uint32_t contentIndex = 0; contentIndex < contentCount; contentIndex++) {
     nsCOMPtr<nsIContent> content =
       CreateGeneratedContent(aState, aParentContent, pseudoStyleContext,
                              contentIndex);
     if (content) {
       container->AppendChildTo(content, false);
     }
   }
   AddFrameConstructionItemsInternal(aState, container, aParentFrame, elemName,
                                     kNameSpaceID_None, true,
                                     pseudoStyleContext,
                                     ITEM_IS_GENERATED_CONTENT, nullptr,
                                     aItems);
 }
 /****************************************************
  **  BEGIN TABLE SECTION
  ****************************************************/
 // The term pseudo frame is being used instead of anonymous frame, since anonymous
 // frame has been used elsewhere to refer to frames that have generated content
 // Return whether the given frame is a table pseudo-frame.  Note that
 // cell-content and table-outer frames have pseudo-types, but are always
 // created, even for non-anonymous cells and tables respectively.  So for those
 // we have to examine the cell or table frame to see whether it's a pseudo
 // frame.  In particular, a lone table caption will have an outer table as its
 // parent, but will also trigger construction of an empty inner table, which
 // will be the one we can examine to see whether the outer was a pseudo-frame.
 static bool
 IsTablePseudo(nsIFrame* aFrame)
 {
   nsIAtom* pseudoType = aFrame->StyleContext()->GetPseudo();
   return pseudoType &&
     (pseudoType == nsCSSAnonBoxes::table ||
      pseudoType == nsCSSAnonBoxes::inlineTable ||
      pseudoType == nsCSSAnonBoxes::tableColGroup ||
      pseudoType == nsCSSAnonBoxes::tableRowGroup ||
      pseudoType == nsCSSAnonBoxes::tableRow ||
      pseudoType == nsCSSAnonBoxes::tableCell ||
      (pseudoType == nsCSSAnonBoxes::cellContent &&
       aFrame->GetParent()->StyleContext()->GetPseudo() ==
         nsCSSAnonBoxes::tableCell) ||
      (pseudoType == nsCSSAnonBoxes::tableOuter &&
       (aFrame->GetFirstPrincipalChild()->StyleContext()->GetPseudo() ==
          nsCSSAnonBoxes::table ||
        aFrame->GetFirstPrincipalChild()->StyleContext()->GetPseudo() ==
          nsCSSAnonBoxes::inlineTable)));
 }
 /* static */
 nsCSSFrameConstructor::ParentType
 nsCSSFrameConstructor::GetParentType(nsIAtom* aFrameType)
 {
   if (aFrameType == nsGkAtoms::tableFrame) {
     return eTypeTable;
   }
   if (aFrameType == nsGkAtoms::tableRowGroupFrame) {
     return eTypeRowGroup;
   }
   if (aFrameType == nsGkAtoms::tableRowFrame) {
     return eTypeRow;
   }
   if (aFrameType == nsGkAtoms::tableColGroupFrame) {
     return eTypeColGroup;
   }
   return eTypeBlock;
 }
 static nsIFrame*
 AdjustCaptionParentFrame(nsIFrame* aParentFrame)
 {
   if (nsGkAtoms::tableFrame == aParentFrame->GetType()) {
     return aParentFrame->GetParent();;
   }
   return aParentFrame;
 }
 /**
  * If the parent frame is a |tableFrame| and the child is a
  * |captionFrame|, then we want to insert the frames beneath the
  * |tableFrame|'s parent frame. Returns |true| if the parent frame
  * needed to be fixed up.
  */
 static bool
 GetCaptionAdjustedParent(nsIFrame*        aParentFrame,
                          const nsIFrame*  aChildFrame,
                          nsIFrame**       aAdjParentFrame)
 {
   *aAdjParentFrame = aParentFrame;
   bool haveCaption = false;
   if (nsGkAtoms::tableCaptionFrame == aChildFrame->GetType()) {
     haveCaption = true;
     *aAdjParentFrame = AdjustCaptionParentFrame(aParentFrame);
   }
   return haveCaption;
 }
 void
 nsCSSFrameConstructor::AdjustParentFrame(nsIFrame* &                  aParentFrame,
                                          const FrameConstructionData* aFCData,
                                          nsStyleContext*              aStyleContext)
 {
   NS_PRECONDITION(aStyleContext, "Must have child's style context");
   NS_PRECONDITION(aFCData, "Must have frame construction data");
   bool tablePart = ((aFCData->mBits & FCDATA_IS_TABLE_PART) != 0);
   if (tablePart && aStyleContext->StyleDisplay()->mDisplay ==
       NS_STYLE_DISPLAY_TABLE_CAPTION) {
     aParentFrame = AdjustCaptionParentFrame(aParentFrame);
   }
 }
 // Pull all the captions present in aItems out  into aCaptions
 static void
 PullOutCaptionFrames(nsFrameItems& aItems, nsFrameItems& aCaptions)
 {
   nsIFrame *child = aItems.FirstChild();
   while (child) {
     nsIFrame *nextSibling = child->GetNextSibling();
     if (nsGkAtoms::tableCaptionFrame == child->GetType()) {
       aItems.RemoveFrame(child);
       aCaptions.AddChild(child);
     }
     child = nextSibling;
   }
 }
 // Construct the outer, inner table frames and the children frames for the table.
 // XXX Page break frames for pseudo table frames are not constructed to avoid the risk
 // associated with revising the pseudo frame mechanism. The long term solution
 // of having frames handle page-break-before/after will solve the problem.
 nsIFrame*
 nsCSSFrameConstructor::ConstructTable(nsFrameConstructorState& aState,
                                       FrameConstructionItem&   aItem,
                                       nsIFrame*                aParentFrame,
                                       const nsStyleDisplay*    aDisplay,
                                       nsFrameItems&            aFrameItems)
 {
   NS_PRECONDITION(aDisplay->mDisplay == NS_STYLE_DISPLAY_TABLE ||
                   aDisplay->mDisplay == NS_STYLE_DISPLAY_INLINE_TABLE,
                   "Unexpected call");
   nsIContent* const content = aItem.mContent;
   nsStyleContext* const styleContext = aItem.mStyleContext;
   const uint32_t nameSpaceID = aItem.mNameSpaceID;
   // create the pseudo SC for the outer table as a child of the inner SC
   nsRefPtr<nsStyleContext> outerStyleContext;
   outerStyleContext = mPresShell->StyleSet()->
     ResolveAnonymousBoxStyle(nsCSSAnonBoxes::tableOuter, styleContext);
   // Create the outer table frame which holds the caption and inner table frame
   nsIFrame* newFrame;
   if (kNameSpaceID_MathML == nameSpaceID)
     newFrame = NS_NewMathMLmtableOuterFrame(mPresShell, outerStyleContext);
   else
     newFrame = NS_NewTableOuterFrame(mPresShell, outerStyleContext);
   nsIFrame* geometricParent =
     aState.GetGeometricParent(outerStyleContext->StyleDisplay(),
                               aParentFrame);
   // Init the table outer frame
   InitAndRestoreFrame(aState, content, geometricParent, newFrame);
   // Create the inner table frame
   nsIFrame* innerFrame;
   if (kNameSpaceID_MathML == nameSpaceID)
     innerFrame = NS_NewMathMLmtableFrame(mPresShell, styleContext);
   else
     innerFrame = NS_NewTableFrame(mPresShell, styleContext);
   InitAndRestoreFrame(aState, content, newFrame, innerFrame);
   // Put the newly created frames into the right child list
   SetInitialSingleChild(newFrame, innerFrame);
   aState.AddChild(newFrame, aFrameItems, content, styleContext, aParentFrame);
   if (!mRootElementFrame) {
     // The frame we're constructing will be the root element frame.
     // Set mRootElementFrame before processing children.
     mRootElementFrame = newFrame;
   }
   nsFrameItems childItems;
   // Process children
   nsFrameConstructorSaveState absoluteSaveState;
   const nsStyleDisplay* display = outerStyleContext->StyleDisplay();
   // Mark the table frame as an absolute container if needed
   newFrame->AddStateBits(NS_FRAME_CAN_HAVE_ABSPOS_CHILDREN);
   if (display->IsPositioned(newFrame)) {
     aState.PushAbsoluteContainingBlock(newFrame, newFrame, absoluteSaveState);
   }
   NS_ASSERTION(aItem.mAnonChildren.IsEmpty(),
                "nsIAnonymousContentCreator::CreateAnonymousContent "
                "implementations for table frames are not currently expected "
                "to output a list where the items have their own children");
   if (aItem.mFCData->mBits & FCDATA_USE_CHILD_ITEMS) {
     ConstructFramesFromItemList(aState, aItem.mChildItems,
                                 innerFrame, childItems);
   } else {
     ProcessChildren(aState, content, styleContext, innerFrame,
                     true, childItems, false, aItem.mPendingBinding);
   }
   nsFrameItems captionItems;
   PullOutCaptionFrames(childItems, captionItems);
   // Set the inner table frame's initial primary list
   innerFrame->SetInitialChildList(kPrincipalList, childItems);
   // Set the outer table frame's secondary childlist lists
   if (captionItems.NotEmpty()) {
     newFrame->SetInitialChildList(nsIFrame::kCaptionList, captionItems);
   }
   return newFrame;
 }
 static void
 MakeTablePartAbsoluteContainingBlockIfNeeded(nsFrameConstructorState&     aState,
                                              const nsStyleDisplay*        aDisplay,
                                              nsFrameConstructorSaveState& aAbsSaveState,
                                              nsIFrame*                    aFrame)
 {
   // If we're positioned, then we need to become an absolute containing block
   // for any absolutely positioned children and register for post-reflow fixup.
   //
   // Note that usually if a frame type can be an absolute containing block, we
   // always set NS_FRAME_CAN_HAVE_ABSPOS_CHILDREN, whether it actually is or not.
   // However, in this case flag serves the additional purpose of indicating that
   // the frame was registered with its table frame. This allows us to avoid the
   // overhead of unregistering the frame in most cases.
   if (aDisplay->IsPositioned(aFrame)) {
     aFrame->AddStateBits(NS_FRAME_CAN_HAVE_ABSPOS_CHILDREN);
     aState.PushAbsoluteContainingBlock(aFrame, aFrame, aAbsSaveState);
     nsTableFrame::RegisterPositionedTablePart(aFrame);
   }
 }
 nsIFrame*
 nsCSSFrameConstructor::ConstructTableRowOrRowGroup(nsFrameConstructorState& aState,
                                                    FrameConstructionItem&   aItem,
                                                    nsIFrame*                aParentFrame,
                                                    const nsStyleDisplay*    aDisplay,
                                                    nsFrameItems&            aFrameItems)
 {
   NS_PRECONDITION(aDisplay->mDisplay == NS_STYLE_DISPLAY_TABLE_ROW ||
                   aDisplay->mDisplay == NS_STYLE_DISPLAY_TABLE_ROW_GROUP ||
                   aDisplay->mDisplay == NS_STYLE_DISPLAY_TABLE_FOOTER_GROUP ||
                   aDisplay->mDisplay == NS_STYLE_DISPLAY_TABLE_HEADER_GROUP,
                   "Unexpected call");
   MOZ_ASSERT(aItem.mStyleContext->StyleDisplay() == aDisplay,
              "Display style doesn't match style context");
   nsIContent* const content = aItem.mContent;
   nsStyleContext* const styleContext = aItem.mStyleContext;
   const uint32_t nameSpaceID = aItem.mNameSpaceID;
   nsIFrame* newFrame;
   if (aDisplay->mDisplay == NS_STYLE_DISPLAY_TABLE_ROW) {
     if (kNameSpaceID_MathML == nameSpaceID)
       newFrame = NS_NewMathMLmtrFrame(mPresShell, styleContext);
     else
       newFrame = NS_NewTableRowFrame(mPresShell, styleContext);
   } else {
     newFrame = NS_NewTableRowGroupFrame(mPresShell, styleContext);
   }
   InitAndRestoreFrame(aState, content, aParentFrame, newFrame);
   nsFrameConstructorSaveState absoluteSaveState;
   MakeTablePartAbsoluteContainingBlockIfNeeded(aState, aDisplay,
                                                absoluteSaveState,
                                                newFrame);
   nsFrameItems childItems;
   NS_ASSERTION(aItem.mAnonChildren.IsEmpty(),
                "nsIAnonymousContentCreator::CreateAnonymousContent "
                "implementations for table frames are not currently expected "
                "to output a list where the items have their own children");
   if (aItem.mFCData->mBits & FCDATA_USE_CHILD_ITEMS) {
     ConstructFramesFromItemList(aState, aItem.mChildItems, newFrame,
                                 childItems);
   } else {
     ProcessChildren(aState, content, styleContext, newFrame,
                     true, childItems, false, aItem.mPendingBinding);
   }
   newFrame->SetInitialChildList(kPrincipalList, childItems);
   aFrameItems.AddChild(newFrame);
   return newFrame;
 }
 nsIFrame*
 nsCSSFrameConstructor::ConstructTableCol(nsFrameConstructorState& aState,
                                          FrameConstructionItem&   aItem,
                                          nsIFrame*                aParentFrame,
                                          const nsStyleDisplay*    aStyleDisplay,
                                          nsFrameItems&            aFrameItems)
 {
   nsIContent* const content = aItem.mContent;
   nsStyleContext* const styleContext = aItem.mStyleContext;
   nsTableColFrame* colFrame = NS_NewTableColFrame(mPresShell, styleContext);
   InitAndRestoreFrame(aState, content, aParentFrame, colFrame);
   NS_ASSERTION(colFrame->StyleContext() == styleContext,
                "Unexpected style context");
   aFrameItems.AddChild(colFrame);
   // construct additional col frames if the col frame has a span > 1
   int32_t span = colFrame->GetSpan();
   for (int32_t spanX = 1; spanX < span; spanX++) {
     nsTableColFrame* newCol = NS_NewTableColFrame(mPresShell, styleContext);
     InitAndRestoreFrame(aState, content, aParentFrame, newCol, false);
     aFrameItems.LastChild()->SetNextContinuation(newCol);
     newCol->SetPrevContinuation(aFrameItems.LastChild());
     aFrameItems.AddChild(newCol);
     newCol->SetColType(eColAnonymousCol);
   }
   return colFrame;
 }
 nsIFrame*
 nsCSSFrameConstructor::ConstructTableCell(nsFrameConstructorState& aState,
                                           FrameConstructionItem&   aItem,
                                           nsIFrame*                aParentFrame,
                                           const nsStyleDisplay*    aDisplay,
                                           nsFrameItems&            aFrameItems)
 {
   NS_PRECONDITION(aDisplay->mDisplay == NS_STYLE_DISPLAY_TABLE_CELL,
                   "Unexpected call");
   nsIContent* const content = aItem.mContent;
   nsStyleContext* const styleContext = aItem.mStyleContext;
   const uint32_t nameSpaceID = aItem.mNameSpaceID;
   bool borderCollapse = IsBorderCollapse(aParentFrame);
   nsIFrame* newFrame;
   // <mtable> is border separate in mathml.css and the MathML code doesn't implement
   // border collapse. For those users who style <mtable> with border collapse,
   // give them the default non-MathML table frames that understand border collapse.
   // This won't break us because MathML table frames are all subclasses of the default
   // table code, and so we can freely mix <mtable> with <mtr> or <tr>, <mtd> or <td>.
   // What will happen is just that non-MathML frames won't understand MathML attributes
   // and will therefore miss the special handling that the MathML code does.
   if (kNameSpaceID_MathML == nameSpaceID && !borderCollapse)
     newFrame = NS_NewMathMLmtdFrame(mPresShell, styleContext);
   else
     // Warning: If you change this and add a wrapper frame around table cell
     // frames, make sure Bug 368554 doesn't regress!
     // See IsInAutoWidthTableCellForQuirk() in nsImageFrame.cpp.
     newFrame = NS_NewTableCellFrame(mPresShell, styleContext, borderCollapse);
   // Initialize the table cell frame
   InitAndRestoreFrame(aState, content, aParentFrame, newFrame);
   // Resolve pseudo style and initialize the body cell frame
   nsRefPtr<nsStyleContext> innerPseudoStyle;
   innerPseudoStyle = mPresShell->StyleSet()->
     ResolveAnonymousBoxStyle(nsCSSAnonBoxes::cellContent, styleContext);
   // Create a block frame that will format the cell's content
   bool isBlock;
   nsIFrame* cellInnerFrame;
   if (kNameSpaceID_MathML == nameSpaceID) {
     cellInnerFrame = NS_NewMathMLmtdInnerFrame(mPresShell, innerPseudoStyle);
     isBlock = false;
   } else {
     cellInnerFrame = NS_NewBlockFormattingContext(mPresShell, innerPseudoStyle);
     isBlock = true;
   }
   InitAndRestoreFrame(aState, content, newFrame, cellInnerFrame);
   nsFrameConstructorSaveState absoluteSaveState;
   MakeTablePartAbsoluteContainingBlockIfNeeded(aState, aDisplay,
                                                absoluteSaveState,
                                                newFrame);
   nsFrameItems childItems;
   NS_ASSERTION(aItem.mAnonChildren.IsEmpty(),
                "nsIAnonymousContentCreator::CreateAnonymousContent "
                "implementations for table frames are not currently expected "
                "to output a list where the items have their own children");
   if (aItem.mFCData->mBits & FCDATA_USE_CHILD_ITEMS) {
     // Need to push ourselves as a float containing block.
     // XXXbz it might be nice to work on getting the parent
     // FrameConstructionItem down into ProcessChildren and just making use of
     // the push there, but that's a bit of work.
     nsFrameConstructorSaveState floatSaveState;
     if (!isBlock) { /* MathML case */
       aState.PushFloatContainingBlock(nullptr, floatSaveState);
     } else {
       aState.PushFloatContainingBlock(cellInnerFrame, floatSaveState);
     }
     ConstructFramesFromItemList(aState, aItem.mChildItems, cellInnerFrame,
                                 childItems);
   } else {
     // Process the child content
     ProcessChildren(aState, content, styleContext, cellInnerFrame,
                     true, childItems, isBlock, aItem.mPendingBinding);
   }
   cellInnerFrame->SetInitialChildList(kPrincipalList, childItems);
   SetInitialSingleChild(newFrame, cellInnerFrame);
   aFrameItems.AddChild(newFrame);
   return newFrame;
 }
 static inline bool
 NeedFrameFor(const nsFrameConstructorState& aState,
              nsIFrame*   aParentFrame,
              nsIContent* aChildContent)
 {
   // XXX the GetContent() != aChildContent check is needed due to bug 135040.
   // Remove it once that's fixed.
   NS_PRECONDITION(!aChildContent->GetPrimaryFrame() ||
                   aState.mCreatingExtraFrames ||
                   aChildContent->GetPrimaryFrame()->GetContent() != aChildContent,
                   "Why did we get called?");
   // don't create a whitespace frame if aParentFrame doesn't want it.
   // always create frames for children in generated content. counter(),
   // quotes, and attr() content can easily change dynamically and we don't
   // want to be reconstructing frames. It's not even clear that these
   // should be considered ignorable just because they evaluate to
   // whitespace.
   // We could handle all this in CreateNeededTablePseudos or some other place
   // after we build our frame construction items, but that would involve
   // creating frame construction items for whitespace kids of
   // eExcludesIgnorableWhitespace frames, where we know we'll be dropping them
   // all anyway, and involve an extra walk down the frame construction item
   // list.
   if (!aParentFrame->IsFrameOfType(nsIFrame::eExcludesIgnorableWhitespace) ||
       aParentFrame->IsGeneratedContentFrame() ||
       !aChildContent->IsNodeOfType(nsINode::eTEXT)) {
     return true;
   }
   aChildContent->SetFlags(NS_CREATE_FRAME_IF_NON_WHITESPACE |
                           NS_REFRAME_IF_WHITESPACE);
   return !aChildContent->TextIsOnlyWhitespace();
 }
 /***********************************************
  * END TABLE SECTION
  ***********************************************/
 static bool CheckOverflow(nsPresContext* aPresContext,
                             const nsStyleDisplay* aDisplay)
 {
   if (aDisplay->mOverflowX == NS_STYLE_OVERFLOW_VISIBLE)
     return false;
   if (aDisplay->mOverflowX == NS_STYLE_OVERFLOW_CLIP)
     aPresContext->SetViewportOverflowOverride(NS_STYLE_OVERFLOW_HIDDEN,
                                               NS_STYLE_OVERFLOW_HIDDEN);
   else
     aPresContext->SetViewportOverflowOverride(aDisplay->mOverflowX,
                                               aDisplay->mOverflowY);
   return true;
 }
 /**
  * This checks the root element and the HTML BODY, if any, for an "overflow" property
  * that should be applied to the viewport. If one is found then we return the
  * element that we took the overflow from (which should then be treated as
  * "overflow:visible"), and we store the overflow style in the prescontext.
  * @return if scroll was propagated from some content node, the content node it
  *         was propagated from.
  */
 nsIContent*
 nsCSSFrameConstructor::PropagateScrollToViewport()
 {
   // Set default
   nsPresContext* presContext = mPresShell->GetPresContext();
   presContext->SetViewportOverflowOverride(NS_STYLE_OVERFLOW_AUTO,
                                            NS_STYLE_OVERFLOW_AUTO);
   // We never mess with the viewport scroll state
   // when printing or in print preview
   if (presContext->IsPaginated()) {
     return nullptr;
   }
   Element* docElement = mDocument->GetRootElement();
   // Check the style on the document root element
   nsStyleSet *styleSet = mPresShell->StyleSet();
   nsRefPtr<nsStyleContext> rootStyle;
   rootStyle = styleSet->ResolveStyleFor(docElement, nullptr);
   if (CheckOverflow(presContext, rootStyle->StyleDisplay())) {
     // tell caller we stole the overflow style from the root element
     return docElement;
   }
   // Don't look in the BODY for non-HTML documents or HTML documents
   // with non-HTML roots
   // XXX this should be earlier; we shouldn't even look at the document root
   // for non-HTML documents. Fix this once we support explicit CSS styling
   // of the viewport
   // XXX what about XHTML?
   nsCOMPtr<nsIDOMHTMLDocument> htmlDoc(do_QueryInterface(mDocument));
   if (!htmlDoc || !docElement->IsHTML()) {
     return nullptr;
   }
   nsCOMPtr<nsIDOMHTMLElement> body;
   htmlDoc->GetBody(getter_AddRefs(body));
   nsCOMPtr<nsIContent> bodyElement = do_QueryInterface(body);
   if (!bodyElement ||
       !bodyElement->NodeInfo()->Equals(nsGkAtoms::body)) {
     // The body is not a <body> tag, it's a <frameset>.
     return nullptr;
   }
   nsRefPtr<nsStyleContext> bodyStyle;
   bodyStyle = styleSet->ResolveStyleFor(bodyElement->AsElement(), rootStyle);
   if (CheckOverflow(presContext, bodyStyle->StyleDisplay())) {
     // tell caller we stole the overflow style from the body element
     return bodyElement;
   }
   return nullptr;
 }
 nsIFrame*
 nsCSSFrameConstructor::ConstructDocElementFrame(Element*                 aDocElement,
                                                 nsILayoutHistoryState*   aFrameState)
 {
   NS_PRECONDITION(mFixedContainingBlock,
                   "No viewport?  Someone forgot to call ConstructRootFrame!");
   NS_PRECONDITION(mFixedContainingBlock == GetRootFrame(),
                   "Unexpected mFixedContainingBlock");
   NS_PRECONDITION(!mDocElementContainingBlock,
                   "Shouldn't have a doc element containing block here");
   // Make sure to call PropagateScrollToViewport before
   // SetUpDocElementContainingBlock, since it sets up our scrollbar state
   // properly.
 #ifdef DEBUG
   nsIContent* propagatedScrollFrom =
 #endif
     PropagateScrollToViewport();
   SetUpDocElementContainingBlock(aDocElement);
   NS_ASSERTION(mDocElementContainingBlock, "Should have parent by now");
   nsFrameConstructorState state(mPresShell, mFixedContainingBlock, nullptr,
                                 nullptr, aFrameState);
   // Initialize the ancestor filter with null for now; we'll push
   // aDocElement once we finish resolving style for it.
   state.mTreeMatchContext.InitAncestors(nullptr);
   // XXXbz why, exactly?
   if (!mTempFrameTreeState)
     state.mPresShell->CaptureHistoryState(getter_AddRefs(mTempFrameTreeState));
   // Make sure that we'll handle restyles for this document element in
   // the future.  We need this, because the document element might
   // have stale restyle bits from a previous frame constructor for
   // this document.  Unlike in AddFrameConstructionItems, it's safe to
   // unset all element restyle flags, since we don't have any
   // siblings.
   aDocElement->UnsetFlags(ELEMENT_ALL_RESTYLE_FLAGS);
   // --------- CREATE AREA OR BOX FRAME -------
   nsRefPtr<nsStyleContext> styleContext;
   styleContext = mPresShell->StyleSet()->ResolveStyleFor(aDocElement,
                                                          nullptr);
   const nsStyleDisplay* display = styleContext->StyleDisplay();
   // Ensure that our XBL bindings are installed.
   if (display->mBinding) {
     // Get the XBL loader.
     nsresult rv;
     bool resolveStyle;
     nsXBLService* xblService = nsXBLService::GetInstance();
     if (!xblService) {
       return nullptr;
     }
     nsRefPtr<nsXBLBinding> binding;
     rv = xblService->LoadBindings(aDocElement, display->mBinding->GetURI(),
                                   display->mBinding->mOriginPrincipal,
                                   getter_AddRefs(binding), &resolveStyle);
     if (NS_FAILED(rv) && rv != NS_ERROR_XBL_BLOCKED)
       return nullptr; // Binding will load asynchronously.
     if (binding) {
       // For backwards compat, keep firing the root's constructor
       // after all of its kids' constructors.  So tell the binding
       // manager about it right now.
       mDocument->BindingManager()->AddToAttachedQueue(binding);
     }
     if (resolveStyle) {
       styleContext = mPresShell->StyleSet()->ResolveStyleFor(aDocElement,
                                                              nullptr);
       display = styleContext->StyleDisplay();
     }
   }
   // --------- IF SCROLLABLE WRAP IN SCROLLFRAME --------
 #ifdef DEBUG
   NS_ASSERTION(!display->IsScrollableOverflow() ||
                state.mPresContext->IsPaginated() ||
                propagatedScrollFrom == aDocElement,
                "Scrollbars should have been propagated to the viewport");
 #endif
   if (MOZ_UNLIKELY(display->mDisplay == NS_STYLE_DISPLAY_NONE)) {
     SetUndisplayedContent(aDocElement, styleContext);
     return nullptr;
   }
   TreeMatchContext::AutoAncestorPusher ancestorPusher(state.mTreeMatchContext);
   ancestorPusher.PushAncestorAndStyleScope(aDocElement);
   // Make sure to start any background image loads for the root element now.
   styleContext->StartBackgroundImageLoads();
   nsFrameConstructorSaveState absoluteSaveState;
   if (mHasRootAbsPosContainingBlock) {
     // Push the absolute containing block now so we can absolutely position
     // the root element
     mDocElementContainingBlock->AddStateBits(NS_FRAME_CAN_HAVE_ABSPOS_CHILDREN);
     state.PushAbsoluteContainingBlock(mDocElementContainingBlock,
                                       mDocElementContainingBlock,
                                       absoluteSaveState);
   }
   // The rules from CSS 2.1, section 9.2.4, have already been applied
   // by the style system, so we can assume that display->mDisplay is
   // either NONE, BLOCK, or TABLE.
   // contentFrame is the primary frame for the root element. newFrame
   // is the frame that will be the child of the initial containing block.
   // These are usually the same frame but they can be different, in
   // particular if the root frame is positioned, in which case
   // contentFrame is the out-of-flow frame and newFrame is the
   // placeholder.
   nsIFrame* contentFrame;
   nsIFrame* newFrame;
   bool processChildren = false;
   // Check whether we need to build a XUL box or SVG root frame
 #ifdef MOZ_XUL
   if (aDocElement->IsXUL()) {
     contentFrame = NS_NewDocElementBoxFrame(mPresShell, styleContext);
     InitAndRestoreFrame(state, aDocElement, mDocElementContainingBlock,
                         contentFrame);
     newFrame = contentFrame;
     processChildren = true;
   }
   else
 #endif
   if (aDocElement->IsSVG()) {
     if (aDocElement->Tag() != nsGkAtoms::svg) {
       return nullptr;
     }
     // We're going to call the right function ourselves, so no need to give a
     // function to this FrameConstructionData.
     // XXXbz on the other hand, if we converted this whole function to
     // FrameConstructionData/Item, then we'd need the right function
     // here... but would probably be able to get away with less code in this
     // function in general.
     // Use a null PendingBinding, since our binding is not in fact pending.
     static const FrameConstructionData rootSVGData = FCDATA_DECL(0, nullptr);
     already_AddRefed<nsStyleContext> extraRef =
       nsRefPtr<nsStyleContext>(styleContext).forget();
     FrameConstructionItem item(&rootSVGData, aDocElement,
                                aDocElement->Tag(), kNameSpaceID_SVG,
                                nullptr, extraRef, true, nullptr);
     nsFrameItems frameItems;
     contentFrame = ConstructOuterSVG(state, item, mDocElementContainingBlock,
                                      styleContext->StyleDisplay(),
                                      frameItems);
     newFrame = frameItems.FirstChild();
     NS_ASSERTION(frameItems.OnlyChild(), "multiple root element frames");
   } else if (display->mDisplay == NS_STYLE_DISPLAY_FLEX) {
     contentFrame = NS_NewFlexContainerFrame(mPresShell, styleContext);
     InitAndRestoreFrame(state, aDocElement, mDocElementContainingBlock,
                         contentFrame);
     newFrame = contentFrame;
     processChildren = true;
   } else if (display->mDisplay == NS_STYLE_DISPLAY_GRID) {
     contentFrame = NS_NewGridContainerFrame(mPresShell, styleContext);
     InitAndRestoreFrame(state, aDocElement, mDocElementContainingBlock,
                         contentFrame);
     newFrame = contentFrame;
     processChildren = true;
   } else if (display->mDisplay == NS_STYLE_DISPLAY_TABLE) {
     // We're going to call the right function ourselves, so no need to give a
     // function to this FrameConstructionData.
     // XXXbz on the other hand, if we converted this whole function to
     // FrameConstructionData/Item, then we'd need the right function
     // here... but would probably be able to get away with less code in this
     // function in general.
     // Use a null PendingBinding, since our binding is not in fact pending.
     static const FrameConstructionData rootTableData = FCDATA_DECL(0, nullptr);
     already_AddRefed<nsStyleContext> extraRef =
       nsRefPtr<nsStyleContext>(styleContext).forget();
     FrameConstructionItem item(&rootTableData, aDocElement,
                                aDocElement->Tag(), kNameSpaceID_None,
                                nullptr, extraRef, true, nullptr);
     nsFrameItems frameItems;
     // if the document is a table then just populate it.
     contentFrame = ConstructTable(state, item, mDocElementContainingBlock,
                                   styleContext->StyleDisplay(),
                                   frameItems);
     newFrame = frameItems.FirstChild();
     NS_ASSERTION(frameItems.OnlyChild(), "multiple root element frames");
   } else {
     MOZ_ASSERT(display->mDisplay == NS_STYLE_DISPLAY_BLOCK,
                "Unhandled display type for root element");
     contentFrame = NS_NewBlockFormattingContext(mPresShell, styleContext);
     nsFrameItems frameItems;
     // Use a null PendingBinding, since our binding is not in fact pending.
     ConstructBlock(state, display, aDocElement,
                    state.GetGeometricParent(display,
                                             mDocElementContainingBlock),
                    mDocElementContainingBlock, styleContext,
                    &contentFrame, frameItems,
                    display->IsPositioned(contentFrame) ? contentFrame : nullptr,
                    nullptr);
     newFrame = frameItems.FirstChild();
     NS_ASSERTION(frameItems.OnlyChild(), "multiple root element frames");
   }
   MOZ_ASSERT(newFrame);
   MOZ_ASSERT(contentFrame);
   NS_ASSERTION(processChildren ? !mRootElementFrame :
                  mRootElementFrame == contentFrame,
                "unexpected mRootElementFrame");
   mRootElementFrame = contentFrame;
   // Figure out which frame has the main style for the document element,
   // assigning it to mRootElementStyleFrame.
   // Backgrounds should be propagated from that frame to the viewport.
   mRootElementStyleFrame = contentFrame->GetParentStyleContextFrame();
   bool isChild = mRootElementStyleFrame &&
                  mRootElementStyleFrame->GetParent() == contentFrame;
   if (!isChild) {
     mRootElementStyleFrame = mRootElementFrame;
   }
   if (processChildren) {
     // Still need to process the child content
     nsFrameItems childItems;
     NS_ASSERTION(!nsLayoutUtils::GetAsBlock(contentFrame) &&
                  !contentFrame->IsFrameOfType(nsIFrame::eSVG),
                  "Only XUL frames should reach here");
     // Use a null PendingBinding, since our binding is not in fact pending.
     ProcessChildren(state, aDocElement, styleContext, contentFrame, true,
                     childItems, false, nullptr);
     // Set the initial child lists
     contentFrame->SetInitialChildList(kPrincipalList, childItems);
   }
   // set the primary frame
   aDocElement->SetPrimaryFrame(contentFrame);
   SetInitialSingleChild(mDocElementContainingBlock, newFrame);
   return newFrame;
 }
 nsIFrame*
 nsCSSFrameConstructor::ConstructRootFrame()
 {
   AUTO_LAYOUT_PHASE_ENTRY_POINT(mPresShell->GetPresContext(), FrameC);
   nsStyleSet *styleSet = mPresShell->StyleSet();
   // Set up our style rule observer.
   // XXXbz wouldn't this make more sense as part of presshell init?
   {
     styleSet->SetBindingManager(mDocument->BindingManager());
   }
   // --------- BUILD VIEWPORT -----------
   nsIFrame*                 viewportFrame = nullptr;
   nsRefPtr<nsStyleContext> viewportPseudoStyle;
   viewportPseudoStyle =
     styleSet->ResolveAnonymousBoxStyle(nsCSSAnonBoxes::viewport, nullptr);
   viewportFrame = NS_NewViewportFrame(mPresShell, viewportPseudoStyle);
   // XXXbz do we _have_ to pass a null content pointer to that frame?
   // Would it really kill us to pass in the root element or something?
   // What would that break?
   viewportFrame->Init(nullptr, nullptr, nullptr);
   // Bind the viewport frame to the root view
   nsView* rootView = mPresShell->GetViewManager()->GetRootView();
   viewportFrame->SetView(rootView);
   nsContainerFrame::SyncFrameViewProperties(mPresShell->GetPresContext(), viewportFrame,
                                             viewportPseudoStyle, rootView);
   nsContainerFrame::SyncWindowProperties(mPresShell->GetPresContext(), viewportFrame,
                                          rootView);
   // The viewport is the containing block for 'fixed' elements
   mFixedContainingBlock = viewportFrame;
   // Make it an absolute container for fixed-pos elements
   mFixedContainingBlock->AddStateBits(NS_FRAME_CAN_HAVE_ABSPOS_CHILDREN);
   mFixedContainingBlock->MarkAsAbsoluteContainingBlock();
   return viewportFrame;
 }
 void
 nsCSSFrameConstructor::SetUpDocElementContainingBlock(nsIContent* aDocElement)
 {
   NS_PRECONDITION(aDocElement, "No element?");
   NS_PRECONDITION(!aDocElement->GetParent(), "Not root content?");
   NS_PRECONDITION(aDocElement->GetCurrentDoc(), "Not in a document?");
   NS_PRECONDITION(aDocElement->GetCurrentDoc()->GetRootElement() ==
                   aDocElement, "Not the root of the document?");
   /*
     how the root frame hierarchy should look
   Galley presentation, non-XUL, with scrolling:
       ViewportFrame [fixed-cb]
         nsHTMLScrollFrame
           nsCanvasFrame [abs-cb]
             root element frame (nsBlockFrame, nsSVGOuterSVGFrame,
                                 nsTableOuterFrame, nsPlaceholderFrame)
   Galley presentation, XUL
       ViewportFrame [fixed-cb]
         nsRootBoxFrame
           root element frame (nsDocElementBoxFrame)
   Print presentation, non-XUL
       ViewportFrame
         nsSimplePageSequenceFrame
           nsPageFrame [fixed-cb]
             nsPageContentFrame
               nsCanvasFrame [abs-cb]
                 root element frame (nsBlockFrame, nsSVGOuterSVGFrame,
                                     nsTableOuterFrame, nsPlaceholderFrame)
   Print-preview presentation, non-XUL
       ViewportFrame
         nsHTMLScrollFrame
           nsSimplePageSequenceFrame
             nsPageFrame [fixed-cb]
               nsPageContentFrame
                 nsCanvasFrame [abs-cb]
                   root element frame (nsBlockFrame, nsSVGOuterSVGFrame,
                                       nsTableOuterFrame, nsPlaceholderFrame)
   Print/print preview of XUL is not supported.
   [fixed-cb]: the default containing block for fixed-pos content
   [abs-cb]: the default containing block for abs-pos content
   Meaning of nsCSSFrameConstructor fields:
     mRootElementFrame is "root element frame".  This is the primary frame for
       the root element.
     mDocElementContainingBlock is the parent of mRootElementFrame
       (i.e. nsCanvasFrame or nsRootBoxFrame)
     mFixedContainingBlock is the [fixed-cb]
     mGfxScrollFrame is the nsHTMLScrollFrame mentioned above, or null if there isn't one
     mPageSequenceFrame is the nsSimplePageSequenceFrame, or null if there isn't one
   */
   // --------- CREATE ROOT FRAME -------
   // Create the root frame. The document element's frame is a child of the
   // root frame.
   //
   // The root frame serves two purposes:
   // - reserves space for any margins needed for the document element's frame
   // - renders the document element's background. This ensures the background covers
   //   the entire canvas as specified by the CSS2 spec
   nsPresContext* presContext = mPresShell->GetPresContext();
   bool isPaginated = presContext->IsRootPaginatedDocument();
   nsIFrame* viewportFrame = mFixedContainingBlock;
   nsStyleContext* viewportPseudoStyle = viewportFrame->StyleContext();
   nsIFrame* rootFrame = nullptr;
   nsIAtom* rootPseudo;
   if (!isPaginated) {
 #ifdef MOZ_XUL
     if (aDocElement->IsXUL())
     {
       // pass a temporary stylecontext, the correct one will be set later
       rootFrame = NS_NewRootBoxFrame(mPresShell, viewportPseudoStyle);
     } else
 #endif
     {
       // pass a temporary stylecontext, the correct one will be set later
       rootFrame = NS_NewCanvasFrame(mPresShell, viewportPseudoStyle);
       mHasRootAbsPosContainingBlock = true;
     }
     rootPseudo = nsCSSAnonBoxes::canvas;
     mDocElementContainingBlock = rootFrame;
   } else {
     // Create a page sequence frame
     rootFrame = NS_NewSimplePageSequenceFrame(mPresShell, viewportPseudoStyle);
     mPageSequenceFrame = rootFrame;
     rootPseudo = nsCSSAnonBoxes::pageSequence;
   }
   // --------- IF SCROLLABLE WRAP IN SCROLLFRAME --------
   // If the device supports scrolling (e.g., in galley mode on the screen and
   // for print-preview, but not when printing), then create a scroll frame that
   // will act as the scrolling mechanism for the viewport.
   // XXX Do we even need a viewport when printing to a printer?
   bool isHTML = aDocElement->IsHTML();
   bool isXUL = false;
   if (!isHTML) {
     isXUL = aDocElement->IsXUL();
   }
   // Never create scrollbars for XUL documents
   bool isScrollable = isPaginated ? presContext->HasPaginatedScrolling() : !isXUL;
   // We no longer need to do overflow propagation here. It's taken care of
   // when we construct frames for the element whose overflow might be
   // propagated
   NS_ASSERTION(!isScrollable || !isXUL,
                "XUL documents should never be scrollable - see above");
   nsIFrame* newFrame = rootFrame;
   nsRefPtr<nsStyleContext> rootPseudoStyle;
   // we must create a state because if the scrollbars are GFX it needs the
   // state to build the scrollbar frames.
   nsFrameConstructorState state(mPresShell, nullptr, nullptr, nullptr);
   // Start off with the viewport as parent; we'll adjust it as needed.
   nsIFrame* parentFrame = viewportFrame;
   nsStyleSet* styleSet = mPresShell->StyleSet();
   // If paginated, make sure we don't put scrollbars in
   if (!isScrollable) {
     rootPseudoStyle = styleSet->ResolveAnonymousBoxStyle(rootPseudo,
                                                          viewportPseudoStyle);
   } else {
       if (rootPseudo == nsCSSAnonBoxes::canvas) {
         rootPseudo = nsCSSAnonBoxes::scrolledCanvas;
       } else {
         NS_ASSERTION(rootPseudo == nsCSSAnonBoxes::pageSequence,
                      "Unknown root pseudo");
         rootPseudo = nsCSSAnonBoxes::scrolledPageSequence;
       }
       // Build the frame. We give it the content we are wrapping which is the
       // document element, the root frame, the parent view port frame, and we
       // should get back the new frame and the scrollable view if one was
       // created.
       // resolve a context for the scrollframe
       nsRefPtr<nsStyleContext>  styleContext;
       styleContext = styleSet->ResolveAnonymousBoxStyle(nsCSSAnonBoxes::viewportScroll,
                                                         viewportPseudoStyle);
       // Note that the viewport scrollframe is always built with
       // overflow:auto style. This forces the scroll frame to create
       // anonymous content for both scrollbars. This is necessary even
       // if the HTML or BODY elements are overriding the viewport
       // scroll style to 'hidden' --- dynamic style changes might put
       // scrollbars back on the viewport and we don't want to have to
       // reframe the viewport to create the scrollbar content.
       newFrame = nullptr;
       rootPseudoStyle = BeginBuildingScrollFrame( state,
                                                   aDocElement,
                                                   styleContext,
                                                   viewportFrame,
                                                   rootPseudo,
                                                   true,
                                                   newFrame);
       parentFrame = newFrame;
       mGfxScrollFrame = newFrame;
   }
   rootFrame->SetStyleContextWithoutNotification(rootPseudoStyle);
   rootFrame->Init(aDocElement, parentFrame, nullptr);
   if (isScrollable) {
     FinishBuildingScrollFrame(parentFrame, rootFrame);
   }
   if (isPaginated) { // paginated
     // Create the first page
     // Set the initial child lists
     nsIFrame* canvasFrame;
     nsIFrame* pageFrame =
       ConstructPageFrame(mPresShell, presContext, rootFrame, nullptr,
                          canvasFrame);
     SetInitialSingleChild(rootFrame, pageFrame);
     // The eventual parent of the document element frame.
     // XXX should this be set for every new page (in ConstructPageFrame)?
     mDocElementContainingBlock = canvasFrame;
     mHasRootAbsPosContainingBlock = true;
   }
   if (viewportFrame->GetStateBits() & NS_FRAME_FIRST_REFLOW) {
     SetInitialSingleChild(viewportFrame, newFrame);
   } else {
     nsFrameList newFrameList(newFrame, newFrame);
     viewportFrame->AppendFrames(kPrincipalList, newFrameList);
   }
 }
 nsIFrame*
 nsCSSFrameConstructor::ConstructPageFrame(nsIPresShell*  aPresShell,
                                           nsPresContext* aPresContext,
                                           nsIFrame*      aParentFrame,
                                           nsIFrame*      aPrevPageFrame,
                                           nsIFrame*&     aCanvasFrame)
 {
   nsStyleContext* parentStyleContext = aParentFrame->StyleContext();
   nsStyleSet *styleSet = aPresShell->StyleSet();
   nsRefPtr<nsStyleContext> pagePseudoStyle;
   pagePseudoStyle = styleSet->ResolveAnonymousBoxStyle(nsCSSAnonBoxes::page,
                                                        parentStyleContext);
   nsIFrame* pageFrame = NS_NewPageFrame(aPresShell, pagePseudoStyle);
   // Initialize the page frame and force it to have a view. This makes printing of
   // the pages easier and faster.
   pageFrame->Init(nullptr, aParentFrame, aPrevPageFrame);
   nsRefPtr<nsStyleContext> pageContentPseudoStyle;
   pageContentPseudoStyle =
     styleSet->ResolveAnonymousBoxStyle(nsCSSAnonBoxes::pageContent,
                                        pagePseudoStyle);
   nsIFrame* pageContentFrame = NS_NewPageContentFrame(aPresShell, pageContentPseudoStyle);
   // Initialize the page content frame and force it to have a view. Also make it the
   // containing block for fixed elements which are repeated on every page.
   nsIFrame* prevPageContentFrame = nullptr;
   if (aPrevPageFrame) {
     prevPageContentFrame = aPrevPageFrame->GetFirstPrincipalChild();
     NS_ASSERTION(prevPageContentFrame, "missing page content frame");
   }
   pageContentFrame->Init(nullptr, pageFrame, prevPageContentFrame);
   SetInitialSingleChild(pageFrame, pageContentFrame);
   mFixedContainingBlock = pageContentFrame;
   // Make it an absolute container for fixed-pos elements
   mFixedContainingBlock->AddStateBits(NS_FRAME_CAN_HAVE_ABSPOS_CHILDREN);
   mFixedContainingBlock->MarkAsAbsoluteContainingBlock();
   nsRefPtr<nsStyleContext> canvasPseudoStyle;
   canvasPseudoStyle = styleSet->ResolveAnonymousBoxStyle(nsCSSAnonBoxes::canvas,
                                                          pageContentPseudoStyle);
   aCanvasFrame = NS_NewCanvasFrame(aPresShell, canvasPseudoStyle);
   nsIFrame* prevCanvasFrame = nullptr;
   if (prevPageContentFrame) {
     prevCanvasFrame = prevPageContentFrame->GetFirstPrincipalChild();
     NS_ASSERTION(prevCanvasFrame, "missing canvas frame");
   }
   aCanvasFrame->Init(nullptr, pageContentFrame, prevCanvasFrame);
   SetInitialSingleChild(pageContentFrame, aCanvasFrame);
   return pageFrame;
 }
 /* static */
 nsIFrame*
 nsCSSFrameConstructor::CreatePlaceholderFrameFor(nsIPresShell*    aPresShell,
                                                  nsIContent*      aContent,
                                                  nsIFrame*        aFrame,
                                                  nsStyleContext*  aStyleContext,
                                                  nsIFrame*        aParentFrame,
                                                  nsIFrame*        aPrevInFlow,
                                                  nsFrameState     aTypeBit)
 {
   nsRefPtr<nsStyleContext> placeholderStyle = aPresShell->StyleSet()->
     ResolveStyleForNonElement(aStyleContext->GetParent());
   // The placeholder frame gets a pseudo style context
   nsPlaceholderFrame* placeholderFrame =
     (nsPlaceholderFrame*)NS_NewPlaceholderFrame(aPresShell, placeholderStyle,
                                                 aTypeBit);
   placeholderFrame->Init(aContent, aParentFrame, aPrevInFlow);
   // The placeholder frame has a pointer back to the out-of-flow frame
   placeholderFrame->SetOutOfFlowFrame(aFrame);
   aFrame->AddStateBits(NS_FRAME_OUT_OF_FLOW);
   // Add mapping from absolutely positioned frame to its placeholder frame
   aPresShell->FrameManager()->RegisterPlaceholderFrame(placeholderFrame);
   return placeholderFrame;
 }
 // Clears any lazy bits set in the range [aStartContent, aEndContent).  If
 // aEndContent is null, that means to clear bits in all siblings starting with
 // aStartContent.  aStartContent must not be null unless aEndContent is also
 // null.  We do this so that when new children are inserted under elements whose
 // frame is a leaf the new children don't cause us to try to construct frames
 // for the existing children again.
 static inline void
 ClearLazyBits(nsIContent* aStartContent, nsIContent* aEndContent)
 {
   NS_PRECONDITION(aStartContent || !aEndContent,
                   "Must have start child if we have an end child");
   for (nsIContent* cur = aStartContent; cur != aEndContent;
        cur = cur->GetNextSibling()) {
     cur->UnsetFlags(NODE_DESCENDANTS_NEED_FRAMES | NODE_NEEDS_FRAME);
   }
 }
 nsIFrame*
 nsCSSFrameConstructor::ConstructSelectFrame(nsFrameConstructorState& aState,
                                             FrameConstructionItem&   aItem,
                                             nsIFrame*                aParentFrame,
                                             const nsStyleDisplay*    aStyleDisplay,
                                             nsFrameItems&            aFrameItems)
 {
   nsIContent* const content = aItem.mContent;
   nsStyleContext* const styleContext = aItem.mStyleContext;
   // Construct a frame-based listbox or combobox
   dom::HTMLSelectElement* sel = dom::HTMLSelectElement::FromContent(content);
   MOZ_ASSERT(sel);
   if (sel->IsCombobox()) {
     // Construct a frame-based combo box.
     // The frame-based combo box is built out of three parts. A display area, a button and
     // a dropdown list. The display area and button are created through anonymous content.
     // The drop-down list's frame is created explicitly. The combobox frame shares its content
     // with the drop-down list.
     nsFrameState flags = NS_BLOCK_FLOAT_MGR;
     nsIFrame* comboboxFrame = NS_NewComboboxControlFrame(mPresShell, styleContext, flags);
     // Save the history state so we don't restore during construction
     // since the complete tree is required before we restore.
     nsILayoutHistoryState *historyState = aState.mFrameState;
     aState.mFrameState = nullptr;
     // Initialize the combobox frame
     InitAndRestoreFrame(aState, content,
                         aState.GetGeometricParent(aStyleDisplay, aParentFrame),
                         comboboxFrame);
     aState.AddChild(comboboxFrame, aFrameItems, content, styleContext,
                     aParentFrame);
     nsIComboboxControlFrame* comboBox = do_QueryFrame(comboboxFrame);
     NS_ASSERTION(comboBox, "NS_NewComboboxControlFrame returned frame that "
                  "doesn't implement nsIComboboxControlFrame");
     // Resolve pseudo element style for the dropdown list
     nsRefPtr<nsStyleContext> listStyle;
     listStyle = mPresShell->StyleSet()->
       ResolveAnonymousBoxStyle(nsCSSAnonBoxes::dropDownList, styleContext);
     // Create a listbox
     nsIFrame* listFrame = NS_NewListControlFrame(mPresShell, listStyle);
     // Notify the listbox that it is being used as a dropdown list.
     nsIListControlFrame * listControlFrame = do_QueryFrame(listFrame);
     if (listControlFrame) {
       listControlFrame->SetComboboxFrame(comboboxFrame);
     }
     // Notify combobox that it should use the listbox as it's popup
     comboBox->SetDropDown(listFrame);
     NS_ASSERTION(!listFrame->IsPositioned(),
                  "Ended up with positioned dropdown list somehow.");
     NS_ASSERTION(!listFrame->IsFloating(),
                  "Ended up with floating dropdown list somehow.");
     // Initialize the scroll frame positioned. Note that it is NOT
     // initialized as absolutely positioned.
     nsIFrame* scrolledFrame = NS_NewSelectsAreaFrame(mPresShell, styleContext, flags);
     InitializeSelectFrame(aState, listFrame, scrolledFrame, content,
                           comboboxFrame, listStyle, true,
                           aItem.mPendingBinding, aFrameItems);
     NS_ASSERTION(listFrame->GetView(), "ListFrame's view is nullptr");
     // Create display and button frames from the combobox's anonymous content.
     // The anonymous content is appended to existing anonymous content for this
     // element (the scrollbars).
     nsFrameItems childItems;
     CreateAnonymousFrames(aState, content, comboboxFrame,
                           aItem.mPendingBinding, childItems);
     comboboxFrame->SetInitialChildList(kPrincipalList, childItems);
     // Initialize the additional popup child list which contains the
     // dropdown list frame.
     nsFrameItems popupItems;
     popupItems.AddChild(listFrame);
     comboboxFrame->SetInitialChildList(nsIFrame::kSelectPopupList,
                                        popupItems);
     aState.mFrameState = historyState;
     if (aState.mFrameState) {
       // Restore frame state for the entire subtree of |comboboxFrame|.
       RestoreFrameState(comboboxFrame, aState.mFrameState);
     }
     return comboboxFrame;
   }
   // Listbox, not combobox
   nsIFrame* listFrame = NS_NewListControlFrame(mPresShell, styleContext);
   nsIFrame* scrolledFrame = NS_NewSelectsAreaFrame(
       mPresShell, styleContext, NS_BLOCK_FLOAT_MGR);
   // ******* this code stolen from Initialze ScrollFrame ********
   // please adjust this code to use BuildScrollFrame.
   InitializeSelectFrame(aState, listFrame, scrolledFrame, content,
                         aParentFrame, styleContext, false,
                         aItem.mPendingBinding, aFrameItems);
   return listFrame;
 }
 /**
  * Used to be InitializeScrollFrame but now it's only used for the select tag
  * But the select tag should really be fixed to use GFX scrollbars that can
  * be create with BuildScrollFrame.
  */
 nsresult
 nsCSSFrameConstructor::InitializeSelectFrame(nsFrameConstructorState& aState,
                                              nsIFrame*                scrollFrame,
                                              nsIFrame*                scrolledFrame,
                                              nsIContent*              aContent,
                                              nsIFrame*                aParentFrame,
                                              nsStyleContext*          aStyleContext,
                                              bool                     aBuildCombobox,
                                              PendingBinding*          aPendingBinding,
                                              nsFrameItems&            aFrameItems)
 {
   const nsStyleDisplay* display = aStyleContext->StyleDisplay();
   // Initialize it
   nsIFrame* geometricParent = aState.GetGeometricParent(display, aParentFrame);
   // We don't call InitAndRestoreFrame for scrollFrame because we can only
   // restore the frame state after its parts have been created (in particular,
   // the scrollable view). So we have to split Init and Restore.
   // Initialize the frame
   scrollFrame->Init(aContent, geometricParent, nullptr);
   if (!aBuildCombobox) {
     aState.AddChild(scrollFrame, aFrameItems, aContent,
                     aStyleContext, aParentFrame);
   }
   if (aBuildCombobox) {
     nsContainerFrame::CreateViewForFrame(scrollFrame, true);
   }
   BuildScrollFrame(aState, aContent, aStyleContext, scrolledFrame,
                    geometricParent, scrollFrame);
   if (aState.mFrameState) {
     // Restore frame state for the scroll frame
     RestoreFrameStateFor(scrollFrame, aState.mFrameState);
   }
   // Process children
   nsFrameItems                childItems;
   ProcessChildren(aState, aContent, aStyleContext, scrolledFrame, false,
                   childItems, false, aPendingBinding);
   // Set the scrolled frame's initial child lists
   scrolledFrame->SetInitialChildList(kPrincipalList, childItems);
   return NS_OK;
 }
 nsIFrame*
 nsCSSFrameConstructor::ConstructFieldSetFrame(nsFrameConstructorState& aState,
                                               FrameConstructionItem&   aItem,
                                               nsIFrame*                aParentFrame,
                                               const nsStyleDisplay*    aStyleDisplay,
                                               nsFrameItems&            aFrameItems)
 {
   nsIContent* const content = aItem.mContent;
   nsStyleContext* const styleContext = aItem.mStyleContext;
   nsIFrame* fieldsetFrame = NS_NewFieldSetFrame(mPresShell, styleContext);
   // Initialize it
   InitAndRestoreFrame(aState, content,
                       aState.GetGeometricParent(aStyleDisplay, aParentFrame),
                       fieldsetFrame);
   // Resolve style and initialize the frame
   nsRefPtr<nsStyleContext> fieldsetContentStyle;
   fieldsetContentStyle = mPresShell->StyleSet()->
     ResolveAnonymousBoxStyle(nsCSSAnonBoxes::fieldsetContent, styleContext);
   const nsStyleDisplay* fieldsetContentDisplay = fieldsetContentStyle->StyleDisplay();
   bool isScrollable = fieldsetContentDisplay->IsScrollableOverflow();
   nsIFrame* scrollFrame = nullptr;
   if (isScrollable) {
     fieldsetContentStyle =
       BeginBuildingScrollFrame(aState, content, fieldsetContentStyle,
                                fieldsetFrame, nsCSSAnonBoxes::scrolledContent,
                                false, scrollFrame);
   }
   nsIFrame* blockFrame = NS_NewBlockFrame(mPresShell, fieldsetContentStyle,
                                           NS_BLOCK_FLOAT_MGR |
                                           NS_BLOCK_MARGIN_ROOT);
   InitAndRestoreFrame(aState, content,
     scrollFrame ? scrollFrame : fieldsetFrame, blockFrame);
   aState.AddChild(fieldsetFrame, aFrameItems, content, styleContext, aParentFrame);
   // Process children
   nsFrameConstructorSaveState absoluteSaveState;
   nsFrameItems                childItems;
   blockFrame->AddStateBits(NS_FRAME_CAN_HAVE_ABSPOS_CHILDREN);
   if (fieldsetFrame->IsPositioned()) {
     aState.PushAbsoluteContainingBlock(blockFrame, fieldsetFrame, absoluteSaveState);
   }
   ProcessChildren(aState, content, styleContext, blockFrame, true,
                   childItems, true, aItem.mPendingBinding);
   nsFrameItems fieldsetKids;
   fieldsetKids.AddChild(scrollFrame ? scrollFrame : blockFrame);
   for (nsFrameList::Enumerator e(childItems); !e.AtEnd(); e.Next()) {
     nsIFrame* child = e.get();
     if (child->GetContentInsertionFrame()->GetType() == nsGkAtoms::legendFrame) {
       // We want the legend to be the first frame in the fieldset child list.
       // That way the EventStateManager will do the right thing when tabbing
       // from a selection point within the legend (bug 236071), which is
       // used for implementing legend access keys (bug 81481).
       // GetAdjustedParentFrame() below depends on this frame order.
       childItems.RemoveFrame(child);
       // Make sure to reparent the legend so it has the fieldset as the parent.
       fieldsetKids.InsertFrame(fieldsetFrame, nullptr, child);
       if (scrollFrame) {
         StickyScrollContainer::NotifyReparentedFrameAcrossScrollFrameBoundary(
             child, blockFrame);
       }
       break;
     }
   }
   if (isScrollable) {
     FinishBuildingScrollFrame(scrollFrame, blockFrame);
   }
   // Set the inner frame's initial child lists
   blockFrame->SetInitialChildList(kPrincipalList, childItems);
   // Set the outer frame's initial child list
   fieldsetFrame->SetInitialChildList(kPrincipalList, fieldsetKids);
   fieldsetFrame->AddStateBits(NS_FRAME_MAY_HAVE_GENERATED_CONTENT);
   // Our new frame returned is the outer frame, which is the fieldset frame.
   return fieldsetFrame;
 }
 static nsIFrame*
 FindAncestorWithGeneratedContentPseudo(nsIFrame* aFrame)
 {
   for (nsIFrame* f = aFrame->GetParent(); f; f = f->GetParent()) {
     NS_ASSERTION(f->IsGeneratedContentFrame(),
                  "should not have exited generated content");
     nsIAtom* pseudo = f->StyleContext()->GetPseudo();
     if (pseudo == nsCSSPseudoElements::before ||
         pseudo == nsCSSPseudoElements::after)
       return f;
   }
   return nullptr;
 }
 #define SIMPLE_FCDATA(_func) FCDATA_DECL(0, _func)
 #define FULL_CTOR_FCDATA(_flags, _func)                             \
   { _flags | FCDATA_FUNC_IS_FULL_CTOR, { nullptr }, _func, nullptr }
 /* static */
 const nsCSSFrameConstructor::FrameConstructionData*
 nsCSSFrameConstructor::FindTextData(nsIFrame* aParentFrame)
 {
   if (aParentFrame && IsFrameForSVG(aParentFrame)) {
     nsIFrame *ancestorFrame =
       nsSVGUtils::GetFirstNonAAncestorFrame(aParentFrame);
     if (ancestorFrame) {
       static const FrameConstructionData sSVGTextData =
         FCDATA_DECL(FCDATA_IS_LINE_PARTICIPANT | FCDATA_IS_SVG_TEXT,
                     NS_NewTextFrame);
       if (ancestorFrame->IsSVGText()) {
         return &sSVGTextData;
       }
     }
     return nullptr;
   }
   static const FrameConstructionData sTextData =
     FCDATA_DECL(FCDATA_IS_LINE_PARTICIPANT, NS_NewTextFrame);
   return &sTextData;
 }
 void
 nsCSSFrameConstructor::ConstructTextFrame(const FrameConstructionData* aData,
                                           nsFrameConstructorState& aState,
                                           nsIContent*              aContent,
                                           nsIFrame*                aParentFrame,
                                           nsStyleContext*          aStyleContext,
                                           nsFrameItems&            aFrameItems)
 {
   NS_PRECONDITION(aData, "Must have frame construction data");
   nsIFrame* newFrame = (*aData->mFunc.mCreationFunc)(mPresShell, aStyleContext);
   InitAndRestoreFrame(aState, aContent, aParentFrame, newFrame);
   // We never need to create a view for a text frame.
   if (newFrame->IsGeneratedContentFrame()) {
     nsAutoPtr<nsGenConInitializer> initializer;
     initializer =
       static_cast<nsGenConInitializer*>(
         aContent->UnsetProperty(nsGkAtoms::genConInitializerProperty));
     if (initializer) {
       if (initializer->mNode->InitTextFrame(initializer->mList,
               FindAncestorWithGeneratedContentPseudo(newFrame), newFrame)) {
         (this->*(initializer->mDirtyAll))();
       }
       initializer->mNode.forget();
     }
   }
   // Add the newly constructed frame to the flow
   aFrameItems.AddChild(newFrame);
   if (!aState.mCreatingExtraFrames)
     aContent->SetPrimaryFrame(newFrame);
 }
 /* static */
 const nsCSSFrameConstructor::FrameConstructionData*
 nsCSSFrameConstructor::FindDataByInt(int32_t aInt,
                                      Element* aElement,
                                      nsStyleContext* aStyleContext,
                                      const FrameConstructionDataByInt* aDataPtr,
                                      uint32_t aDataLength)
 {
   for (const FrameConstructionDataByInt *curData = aDataPtr,
          *endData = aDataPtr + aDataLength;
        curData != endData;
        ++curData) {
     if (curData->mInt == aInt) {
       const FrameConstructionData* data = &curData->mData;
       if (data->mBits & FCDATA_FUNC_IS_DATA_GETTER) {
         return data->mFunc.mDataGetter(aElement, aStyleContext);
       }
       return data;
     }
   }
   return nullptr;
 }
 /* static */
 const nsCSSFrameConstructor::FrameConstructionData*
 nsCSSFrameConstructor::FindDataByTag(nsIAtom* aTag,
                                      Element* aElement,
                                      nsStyleContext* aStyleContext,
                                      const FrameConstructionDataByTag* aDataPtr,
                                      uint32_t aDataLength)
 {
   for (const FrameConstructionDataByTag *curData = aDataPtr,
          *endData = aDataPtr + aDataLength;
        curData != endData;
        ++curData) {
     if (*curData->mTag == aTag) {
       const FrameConstructionData* data = &curData->mData;
       if (data->mBits & FCDATA_FUNC_IS_DATA_GETTER) {
         return data->mFunc.mDataGetter(aElement, aStyleContext);
       }
       return data;
     }
   }
   return nullptr;
 }
 #define SUPPRESS_FCDATA() FCDATA_DECL(FCDATA_SUPPRESS_FRAME, nullptr)
 #define SIMPLE_INT_CREATE(_int, _func) { _int, SIMPLE_FCDATA(_func) }
 #define SIMPLE_INT_CHAIN(_int, _func)                       \
   { _int, FCDATA_DECL(FCDATA_FUNC_IS_DATA_GETTER, _func) }
 #define COMPLEX_INT_CREATE(_int, _func)         \
   { _int, FULL_CTOR_FCDATA(0, _func) }
 #define SIMPLE_TAG_CREATE(_tag, _func)          \
   { &nsGkAtoms::_tag, SIMPLE_FCDATA(_func) }
 #define SIMPLE_TAG_CHAIN(_tag, _func)                                   \
   { &nsGkAtoms::_tag, FCDATA_DECL(FCDATA_FUNC_IS_DATA_GETTER,  _func) }
 #define COMPLEX_TAG_CREATE(_tag, _func)             \
   { &nsGkAtoms::_tag, FULL_CTOR_FCDATA(0, _func) }
 static bool
 IsFrameForFieldSet(nsIFrame* aFrame, nsIAtom* aFrameType)
 {
   nsIAtom* pseudo = aFrame->StyleContext()->GetPseudo();
   if (pseudo == nsCSSAnonBoxes::fieldsetContent ||
       pseudo == nsCSSAnonBoxes::scrolledContent) {
     return IsFrameForFieldSet(aFrame->GetParent(), aFrame->GetParent()->GetType());
   }
   return aFrameType == nsGkAtoms::fieldSetFrame;
 }
 /* static */
 const nsCSSFrameConstructor::FrameConstructionData*
 nsCSSFrameConstructor::FindHTMLData(Element* aElement,
                                     nsIAtom* aTag,
                                     int32_t aNameSpaceID,
                                     nsIFrame* aParentFrame,
                                     nsStyleContext* aStyleContext)
 {
   // Ignore the tag if it's not HTML content and if it doesn't extend (via XBL)
   // a valid HTML namespace.  This check must match the one in
   // ShouldHaveFirstLineStyle.
   if (aNameSpaceID != kNameSpaceID_XHTML) {
     return nullptr;
   }
   NS_ASSERTION(!aParentFrame ||
                aParentFrame->StyleContext()->GetPseudo() !=
                  nsCSSAnonBoxes::fieldsetContent ||
                aParentFrame->GetParent()->GetType() == nsGkAtoms::fieldSetFrame,
                "Unexpected parent for fieldset content anon box");
   if (aTag == nsGkAtoms::legend &&
       (!aParentFrame ||
        !IsFrameForFieldSet(aParentFrame, aParentFrame->GetType()) ||
        !aElement->GetParent() ||
        !aElement->GetParent()->IsHTML(nsGkAtoms::fieldset) ||
        aStyleContext->StyleDisplay()->IsFloatingStyle() ||
        aStyleContext->StyleDisplay()->IsAbsolutelyPositionedStyle())) {
     // <legend> is only special inside fieldset, check both the frame tree
     // parent and content tree parent due to XBL issues. For floated or
     // absolutely positioned legends we want to construct by display type and
     // not do special legend stuff.
     // XXXbz it would be nice if we could just decide this based on the parent
     // tag, and hence just use a SIMPLE_TAG_CHAIN for legend below, but the
     // fact that with XBL we could end up with this legend element in some
     // totally weird insertion point makes that chancy, I think.
     return nullptr;
   }
   static const FrameConstructionDataByTag sHTMLData[] = {
     SIMPLE_TAG_CHAIN(img, nsCSSFrameConstructor::FindImgData),
     SIMPLE_TAG_CHAIN(mozgeneratedcontentimage,
                      nsCSSFrameConstructor::FindImgData),
     { &nsGkAtoms::br,
       FCDATA_DECL(FCDATA_IS_LINE_PARTICIPANT | FCDATA_IS_LINE_BREAK,
                   NS_NewBRFrame) },
     SIMPLE_TAG_CREATE(wbr, NS_NewWBRFrame),
     SIMPLE_TAG_CHAIN(input, nsCSSFrameConstructor::FindInputData),
     SIMPLE_TAG_CREATE(textarea, NS_NewTextControlFrame),
     COMPLEX_TAG_CREATE(select, &nsCSSFrameConstructor::ConstructSelectFrame),
     SIMPLE_TAG_CHAIN(object, nsCSSFrameConstructor::FindObjectData),
     SIMPLE_TAG_CHAIN(applet, nsCSSFrameConstructor::FindObjectData),
     SIMPLE_TAG_CHAIN(embed, nsCSSFrameConstructor::FindObjectData),
     COMPLEX_TAG_CREATE(fieldset,
                        &nsCSSFrameConstructor::ConstructFieldSetFrame),
     { &nsGkAtoms::legend,
       FCDATA_DECL(FCDATA_ALLOW_BLOCK_STYLES | FCDATA_MAY_NEED_SCROLLFRAME,
                   NS_NewLegendFrame) },
     SIMPLE_TAG_CREATE(frameset, NS_NewHTMLFramesetFrame),
     SIMPLE_TAG_CREATE(iframe, NS_NewSubDocumentFrame),
     { &nsGkAtoms::button,
       FCDATA_WITH_WRAPPING_BLOCK(FCDATA_ALLOW_BLOCK_STYLES,
                                  NS_NewHTMLButtonControlFrame,
                                  nsCSSAnonBoxes::buttonContent) },
     SIMPLE_TAG_CHAIN(canvas, nsCSSFrameConstructor::FindCanvasData),
     SIMPLE_TAG_CREATE(video, NS_NewHTMLVideoFrame),
     SIMPLE_TAG_CREATE(audio, NS_NewHTMLVideoFrame),
     SIMPLE_TAG_CREATE(progress, NS_NewProgressFrame),
     SIMPLE_TAG_CREATE(meter, NS_NewMeterFrame)
   };
   return FindDataByTag(aTag, aElement, aStyleContext, sHTMLData,
                        ArrayLength(sHTMLData));
 }
 /* static */
 const nsCSSFrameConstructor::FrameConstructionData*
 nsCSSFrameConstructor::FindImgData(Element* aElement,
                                    nsStyleContext* aStyleContext)
 {
   if (!nsImageFrame::ShouldCreateImageFrameFor(aElement, aStyleContext)) {
     return nullptr;
   }
   static const FrameConstructionData sImgData = SIMPLE_FCDATA(NS_NewImageFrame);
   return &sImgData;
 }
 /* static */
 const nsCSSFrameConstructor::FrameConstructionData*
 nsCSSFrameConstructor::FindImgControlData(Element* aElement,
                                           nsStyleContext* aStyleContext)
 {
   if (!nsImageFrame::ShouldCreateImageFrameFor(aElement, aStyleContext)) {
     return nullptr;
   }
   static const FrameConstructionData sImgControlData =
     SIMPLE_FCDATA(NS_NewImageControlFrame);
   return &sImgControlData;
 }
 /* static */
 const nsCSSFrameConstructor::FrameConstructionData*
 nsCSSFrameConstructor::FindInputData(Element* aElement,
                                      nsStyleContext* aStyleContext)
 {
   static const FrameConstructionDataByInt sInputData[] = {
     SIMPLE_INT_CREATE(NS_FORM_INPUT_CHECKBOX, NS_NewGfxCheckboxControlFrame),
     SIMPLE_INT_CREATE(NS_FORM_INPUT_RADIO, NS_NewGfxRadioControlFrame),
     SIMPLE_INT_CREATE(NS_FORM_INPUT_FILE, NS_NewFileControlFrame),
     SIMPLE_INT_CHAIN(NS_FORM_INPUT_IMAGE,
                      nsCSSFrameConstructor::FindImgControlData),
     SIMPLE_INT_CREATE(NS_FORM_INPUT_EMAIL, NS_NewTextControlFrame),
     SIMPLE_INT_CREATE(NS_FORM_INPUT_SEARCH, NS_NewTextControlFrame),
     SIMPLE_INT_CREATE(NS_FORM_INPUT_TEXT, NS_NewTextControlFrame),
     SIMPLE_INT_CREATE(NS_FORM_INPUT_TEL, NS_NewTextControlFrame),
     SIMPLE_INT_CREATE(NS_FORM_INPUT_URL, NS_NewTextControlFrame),
     SIMPLE_INT_CREATE(NS_FORM_INPUT_RANGE, NS_NewRangeFrame),
     SIMPLE_INT_CREATE(NS_FORM_INPUT_PASSWORD, NS_NewTextControlFrame),
     { NS_FORM_INPUT_COLOR,
       FCDATA_WITH_WRAPPING_BLOCK(0, NS_NewColorControlFrame,
                                  nsCSSAnonBoxes::buttonContent) },
     // TODO: this is temporary until a frame is written: bug 635240.
     SIMPLE_INT_CREATE(NS_FORM_INPUT_NUMBER, NS_NewNumberControlFrame),
     // TODO: this is temporary until a frame is written: bug 773205.
     SIMPLE_INT_CREATE(NS_FORM_INPUT_DATE, NS_NewTextControlFrame),
     // TODO: this is temporary until a frame is written: bug 773205
     SIMPLE_INT_CREATE(NS_FORM_INPUT_TIME, NS_NewTextControlFrame),
     { NS_FORM_INPUT_SUBMIT,
       FCDATA_WITH_WRAPPING_BLOCK(0, NS_NewGfxButtonControlFrame,
                                  nsCSSAnonBoxes::buttonContent) },
     { NS_FORM_INPUT_RESET,
       FCDATA_WITH_WRAPPING_BLOCK(0, NS_NewGfxButtonControlFrame,
                                  nsCSSAnonBoxes::buttonContent) },
     { NS_FORM_INPUT_BUTTON,
       FCDATA_WITH_WRAPPING_BLOCK(0, NS_NewGfxButtonControlFrame,
                                  nsCSSAnonBoxes::buttonContent) }
     // Keeping hidden inputs out of here on purpose for so they get frames by
     // display (in practice, none).
   };
   nsCOMPtr<nsIFormControl> control = do_QueryInterface(aElement);
   NS_ASSERTION(control, "input doesn't implement nsIFormControl?");
   return FindDataByInt(control->GetType(), aElement, aStyleContext,
                        sInputData, ArrayLength(sInputData));
 }
 /* static */
 const nsCSSFrameConstructor::FrameConstructionData*
 nsCSSFrameConstructor::FindObjectData(Element* aElement,
                                       nsStyleContext* aStyleContext)
 {
   // GetDisplayedType isn't necessarily nsIObjectLoadingContent::TYPE_NULL for
   // cases when the object is broken/suppressed/etc (e.g. a broken image), but
   // we want to treat those cases as TYPE_NULL
   uint32_t type;
   if (aElement->State().HasAtLeastOneOfStates(NS_EVENT_STATE_BROKEN |
                                               NS_EVENT_STATE_USERDISABLED |
                                               NS_EVENT_STATE_SUPPRESSED)) {
     type = nsIObjectLoadingContent::TYPE_NULL;
   } else {
     nsCOMPtr<nsIObjectLoadingContent> objContent(do_QueryInterface(aElement));
     NS_ASSERTION(objContent,
                  "applet, embed and object must implement "
                  "nsIObjectLoadingContent!");
     objContent->GetDisplayedType(&type);
   }
   static const FrameConstructionDataByInt sObjectData[] = {
     SIMPLE_INT_CREATE(nsIObjectLoadingContent::TYPE_LOADING,
                       NS_NewEmptyFrame),
     SIMPLE_INT_CREATE(nsIObjectLoadingContent::TYPE_PLUGIN,
                       NS_NewObjectFrame),
     SIMPLE_INT_CREATE(nsIObjectLoadingContent::TYPE_IMAGE,
                       NS_NewImageFrame),
     SIMPLE_INT_CREATE(nsIObjectLoadingContent::TYPE_DOCUMENT,
                       NS_NewSubDocumentFrame)
     // Nothing for TYPE_NULL so we'll construct frames by display there
   };
   return FindDataByInt((int32_t)type, aElement, aStyleContext,
                        sObjectData, ArrayLength(sObjectData));
 }
 /* static */
 const nsCSSFrameConstructor::FrameConstructionData*
 nsCSSFrameConstructor::FindCanvasData(Element* aElement,
                                       nsStyleContext* aStyleContext)
 {
   // We want to check whether script is enabled on the document that
   // could be painting to the canvas.  That's the owner document of
   // the canvas, except when the owner document is a static document,
   // in which case it's the original document it was cloned from.
   nsIDocument* doc = aElement->OwnerDoc();
   if (doc->IsStaticDocument()) {
     doc = doc->GetOriginalDocument();
   }
   if (!doc->IsScriptEnabled()) {
     return nullptr;
   }
   static const FrameConstructionData sCanvasData =
     FCDATA_WITH_WRAPPING_BLOCK(0, NS_NewHTMLCanvasFrame,
                                nsCSSAnonBoxes::htmlCanvasContent);
   return &sCanvasData;
 }
 void
 nsCSSFrameConstructor::ConstructFrameFromItemInternal(FrameConstructionItem& aItem,
                                                       nsFrameConstructorState& aState,
                                                       nsIFrame* aParentFrame,
                                                       nsFrameItems& aFrameItems)
 {
   const FrameConstructionData* data = aItem.mFCData;
   NS_ASSERTION(data, "Must have frame construction data");
   uint32_t bits = data->mBits;
   NS_ASSERTION(!(bits & FCDATA_FUNC_IS_DATA_GETTER),
                "Should have dealt with this inside the data finder");
   // Some sets of bits are not compatible with each other
 #define CHECK_ONLY_ONE_BIT(_bit1, _bit2)               \
   NS_ASSERTION(!(bits & _bit1) || !(bits & _bit2),     \
                "Only one of these bits should be set")
   CHECK_ONLY_ONE_BIT(FCDATA_FUNC_IS_FULL_CTOR, FCDATA_FORCE_NULL_ABSPOS_CONTAINER);
   CHECK_ONLY_ONE_BIT(FCDATA_FUNC_IS_FULL_CTOR, FCDATA_WRAP_KIDS_IN_BLOCKS);
   CHECK_ONLY_ONE_BIT(FCDATA_FUNC_IS_FULL_CTOR, FCDATA_MAY_NEED_SCROLLFRAME);
   CHECK_ONLY_ONE_BIT(FCDATA_FUNC_IS_FULL_CTOR, FCDATA_IS_POPUP);
   CHECK_ONLY_ONE_BIT(FCDATA_FUNC_IS_FULL_CTOR, FCDATA_SKIP_ABSPOS_PUSH);
   CHECK_ONLY_ONE_BIT(FCDATA_FUNC_IS_FULL_CTOR,
                      FCDATA_DISALLOW_GENERATED_CONTENT);
   CHECK_ONLY_ONE_BIT(FCDATA_FUNC_IS_FULL_CTOR, FCDATA_ALLOW_BLOCK_STYLES);
   CHECK_ONLY_ONE_BIT(FCDATA_FUNC_IS_FULL_CTOR,
                      FCDATA_CREATE_BLOCK_WRAPPER_FOR_ALL_KIDS);
   CHECK_ONLY_ONE_BIT(FCDATA_WRAP_KIDS_IN_BLOCKS,
                      FCDATA_CREATE_BLOCK_WRAPPER_FOR_ALL_KIDS);
 #undef CHECK_ONLY_ONE_BIT
   NS_ASSERTION(!(bits & FCDATA_FORCED_NON_SCROLLABLE_BLOCK) ||
                ((bits & FCDATA_FUNC_IS_FULL_CTOR) &&
                 data->mFullConstructor ==
                   &nsCSSFrameConstructor::ConstructNonScrollableBlock),
                "Unexpected FCDATA_FORCED_NON_SCROLLABLE_BLOCK flag");
   // Don't create a subdocument frame for iframes if we're creating extra frames
   if (aState.mCreatingExtraFrames && aItem.mContent->IsHTML() &&
       aItem.mContent->Tag() == nsGkAtoms::iframe)
   {
     return;
   }
   nsStyleContext* const styleContext = aItem.mStyleContext;
   const nsStyleDisplay* display = styleContext->StyleDisplay();
   nsIContent* const content = aItem.mContent;
   // Get the parent of the content and check if it is a XBL children element.
   // Push the children element as an ancestor here because it does
   // not have a frame and would not otherwise be pushed as an ancestor. It is
   // necessary to do so in order to correctly handle style resolution on
   // descendants.
   nsIContent* parent = content->GetParent();
   TreeMatchContext::AutoAncestorPusher
     insertionPointPusher(aState.mTreeMatchContext);
   if (parent && nsContentUtils::IsContentInsertionPoint(parent)) {
     if (aState.mTreeMatchContext.mAncestorFilter.HasFilter()) {
       insertionPointPusher.PushAncestorAndStyleScope(parent);
     } else {
       insertionPointPusher.PushStyleScope(parent);
     }
   }
   // Push the content as a style ancestor now, so we don't have to do
   // it in our various full-constructor functions.  In particular,
   // since a number of full-constructor functions don't actually call
   // ProcessChildren in some cases (e.g. for CSS anonymous table boxes
   // or for situations where only anonymouse children are having
   // frames constructed), this is the best place to bottleneck the
   // pushing of the content instead of having to do it in multiple
   // places.
   TreeMatchContext::AutoAncestorPusher
     ancestorPusher(aState.mTreeMatchContext);
   if (aState.mTreeMatchContext.mAncestorFilter.HasFilter()) {
     ancestorPusher.PushAncestorAndStyleScope(content);
   } else {
     ancestorPusher.PushStyleScope(content);
   }
   nsIFrame* newFrame;
   nsIFrame* primaryFrame;
   if (bits & FCDATA_FUNC_IS_FULL_CTOR) {
     newFrame =
       (this->*(data->mFullConstructor))(aState, aItem, aParentFrame,
                                         display, aFrameItems);
     MOZ_ASSERT(newFrame, "Full constructor failed");
     primaryFrame = newFrame;
   } else {
     newFrame =
       (*data->mFunc.mCreationFunc)(mPresShell, styleContext);
     bool allowOutOfFlow = !(bits & FCDATA_DISALLOW_OUT_OF_FLOW);
     bool isPopup = aItem.mIsPopup;
     NS_ASSERTION(!isPopup ||
                  (aState.mPopupItems.containingBlock &&
                   aState.mPopupItems.containingBlock->GetType() ==
                     nsGkAtoms::popupSetFrame),
                  "Should have a containing block here!");
     nsIFrame* geometricParent =
       isPopup ? aState.mPopupItems.containingBlock :
       (allowOutOfFlow ? aState.GetGeometricParent(display, aParentFrame)
                       : aParentFrame);
     // Must init frameToAddToList to null, since it's inout
     nsIFrame* frameToAddToList = nullptr;
     if ((bits & FCDATA_MAY_NEED_SCROLLFRAME) &&
         display->IsScrollableOverflow()) {
       BuildScrollFrame(aState, content, styleContext, newFrame,
                        geometricParent, frameToAddToList);
     } else {
       InitAndRestoreFrame(aState, content, geometricParent, newFrame);
       // See whether we need to create a view
       nsContainerFrame::CreateViewForFrame(newFrame, false);
       frameToAddToList = newFrame;
     }
     // Use frameToAddToList as the primary frame.  In the non-scrollframe case
     // they're equal, but in the scrollframe case newFrame is the scrolled
     // frame, while frameToAddToList is the scrollframe (and should be the
     // primary frame).
     primaryFrame = frameToAddToList;
     // If we need to create a block formatting context to wrap our
     // kids, do it now.
     const nsStyleDisplay* maybeAbsoluteContainingBlockDisplay = display;
     nsIFrame* maybeAbsoluteContainingBlock = newFrame;
     nsIFrame* possiblyLeafFrame = newFrame;
     if (bits & FCDATA_CREATE_BLOCK_WRAPPER_FOR_ALL_KIDS) {
       nsRefPtr<nsStyleContext> blockContext;
       blockContext =
         mPresShell->StyleSet()->ResolveAnonymousBoxStyle(*data->mAnonBoxPseudo,
                                                          styleContext);
       nsIFrame* blockFrame =
         NS_NewBlockFormattingContext(mPresShell, blockContext);
       InitAndRestoreFrame(aState, content, newFrame, blockFrame);
       SetInitialSingleChild(newFrame, blockFrame);
       // Now figure out whether newFrame or blockFrame should be the
       // absolute container.  It should be the latter if it's
       // positioned, otherwise the former.
       const nsStyleDisplay* blockDisplay = blockContext->StyleDisplay();
       if (blockDisplay->IsPositioned(blockFrame)) {
         maybeAbsoluteContainingBlockDisplay = blockDisplay;
         maybeAbsoluteContainingBlock = blockFrame;
       }
       // Our kids should go into the blockFrame
       newFrame = blockFrame;
     }
     aState.AddChild(frameToAddToList, aFrameItems, content, styleContext,
                     aParentFrame, allowOutOfFlow, allowOutOfFlow, isPopup);
 #ifdef MOZ_XUL
     // Icky XUL stuff, sadly
     if (aItem.mIsRootPopupgroup) {
       NS_ASSERTION(nsIRootBox::GetRootBox(mPresShell) &&
                    nsIRootBox::GetRootBox(mPresShell)->GetPopupSetFrame() ==
                      newFrame,
                    "Unexpected PopupSetFrame");
       aState.mPopupItems.containingBlock = newFrame;
       aState.mHavePendingPopupgroup = false;
     }
 #endif /* MOZ_XUL */
     // Process the child content if requested
     nsFrameItems childItems;
     nsFrameConstructorSaveState absoluteSaveState;
     if (bits & FCDATA_FORCE_NULL_ABSPOS_CONTAINER) {
       aState.PushAbsoluteContainingBlock(nullptr, nullptr, absoluteSaveState);
     } else if (!(bits & FCDATA_SKIP_ABSPOS_PUSH)) {
       nsIFrame* cb = maybeAbsoluteContainingBlock;
       cb->AddStateBits(NS_FRAME_CAN_HAVE_ABSPOS_CHILDREN);
       // This check is identical to nsStyleDisplay::IsPositioned except without
       // the assertion that the style display and frame match. When constructing
       // scroll frames we intentionally use the style display for the outer, but
       // make the inner the containing block.
       if ((maybeAbsoluteContainingBlockDisplay->IsAbsolutelyPositionedStyle() ||
            maybeAbsoluteContainingBlockDisplay->IsRelativelyPositionedStyle() ||
            (maybeAbsoluteContainingBlockDisplay->HasTransformStyle() &&
             cb->IsFrameOfType(nsIFrame::eSupportsCSSTransforms)) ||
            maybeAbsoluteContainingBlockDisplay->HasPerspectiveStyle()) &&
           !cb->IsSVGText()) {
         aState.PushAbsoluteContainingBlock(cb, cb, absoluteSaveState);
       }
     }
     if (!aItem.mAnonChildren.IsEmpty()) {
       NS_ASSERTION(!(bits & FCDATA_USE_CHILD_ITEMS),
                    "We should not have both anonymous and non-anonymous "
                    "children in a given FrameConstructorItem");
       AddFCItemsForAnonymousContent(aState, newFrame, aItem.mAnonChildren,
                                     aItem.mChildItems);
       bits |= FCDATA_USE_CHILD_ITEMS;
     }
     if (bits & FCDATA_USE_CHILD_ITEMS) {
       nsFrameConstructorSaveState floatSaveState;
       if (ShouldSuppressFloatingOfDescendants(newFrame)) {
         aState.PushFloatContainingBlock(nullptr, floatSaveState);
       } else if (newFrame->IsFloatContainingBlock()) {
         aState.PushFloatContainingBlock(newFrame, floatSaveState);
       }
       ConstructFramesFromItemList(aState, aItem.mChildItems, newFrame,
                                   childItems);
     } else {
       // Process the child frames.
       ProcessChildren(aState, content, styleContext, newFrame,
                       !(bits & FCDATA_DISALLOW_GENERATED_CONTENT),
                       childItems,
                       (bits & FCDATA_ALLOW_BLOCK_STYLES) != 0,
                       aItem.mPendingBinding, possiblyLeafFrame);
     }
 #ifdef MOZ_XUL
     // More icky XUL stuff
     if (aItem.mNameSpaceID == kNameSpaceID_XUL &&
         (aItem.mTag == nsGkAtoms::treechildren || // trees always need titletips
          content->HasAttr(kNameSpaceID_None, nsGkAtoms::tooltiptext) ||
          content->HasAttr(kNameSpaceID_None, nsGkAtoms::tooltip))) {
       nsIRootBox* rootBox = nsIRootBox::GetRootBox(mPresShell);
       if (rootBox) {
         rootBox->AddTooltipSupport(content);
       }
     }
 #endif
     if (bits & FCDATA_WRAP_KIDS_IN_BLOCKS) {
       nsFrameItems newItems;
       nsFrameItems currentBlockItems;
       nsIFrame* f;
       while ((f = childItems.FirstChild()) != nullptr) {
         bool wrapFrame = IsInlineFrame(f) || IsFramePartOfIBSplit(f);
         if (!wrapFrame) {
           FlushAccumulatedBlock(aState, content, newFrame,
                                 currentBlockItems, newItems);
         }
         childItems.RemoveFrame(f);
         if (wrapFrame) {
           currentBlockItems.AddChild(f);
         } else {
           newItems.AddChild(f);
         }
       }
       FlushAccumulatedBlock(aState, content, newFrame,
                             currentBlockItems, newItems);
       if (childItems.NotEmpty()) {
         // an error must have occurred, delete unprocessed frames
         childItems.DestroyFrames();
       }
       childItems = newItems;
     }
     // Set the frame's initial child list
     // Note that MathML depends on this being called even if
     // childItems is empty!
     newFrame->SetInitialChildList(kPrincipalList, childItems);
   }
   NS_ASSERTION(newFrame->IsFrameOfType(nsIFrame::eLineParticipant) ==
                ((bits & FCDATA_IS_LINE_PARTICIPANT) != 0),
                "Incorrectly set FCDATA_IS_LINE_PARTICIPANT bits");
   if (aItem.mIsAnonymousContentCreatorContent) {
     primaryFrame->AddStateBits(NS_FRAME_ANONYMOUSCONTENTCREATOR_CONTENT);
   }
   // Even if mCreatingExtraFrames is set, we may need to SetPrimaryFrame for
   // generated content that doesn't have one yet.  Note that we have to examine
   // the frame bit, because by this point mIsGeneratedContent has been cleared
   // on aItem.
   if ((!aState.mCreatingExtraFrames ||
        ((primaryFrame->GetStateBits() & NS_FRAME_GENERATED_CONTENT) &&
         !aItem.mContent->GetPrimaryFrame())) &&
        !(bits & FCDATA_SKIP_FRAMESET)) {
     aItem.mContent->SetPrimaryFrame(primaryFrame);
   }
 }
 // after the node has been constructed and initialized create any
 // anonymous content a node needs.
 nsresult
 nsCSSFrameConstructor::CreateAnonymousFrames(nsFrameConstructorState& aState,
                                              nsIContent*              aParent,
                                              nsIFrame*                aParentFrame,
                                              PendingBinding*          aPendingBinding,
                                              nsFrameItems&            aChildItems)
 {
   nsAutoTArray<nsIAnonymousContentCreator::ContentInfo, 4> newAnonymousItems;
   nsresult rv = GetAnonymousContent(aParent, aParentFrame, newAnonymousItems);
   NS_ENSURE_SUCCESS(rv, rv);
   uint32_t count = newAnonymousItems.Length();
   if (count == 0) {
     return NS_OK;
   }
   nsFrameConstructorState::PendingBindingAutoPusher pusher(aState,
                                                            aPendingBinding);
   TreeMatchContext::AutoAncestorPusher ancestorPusher(aState.mTreeMatchContext);
   if (aState.mTreeMatchContext.mAncestorFilter.HasFilter()) {
     ancestorPusher.PushAncestorAndStyleScope(aParent->AsElement());
   } else {
     ancestorPusher.PushStyleScope(aParent->AsElement());
   }
   nsIAnonymousContentCreator* creator = do_QueryFrame(aParentFrame);
   NS_ASSERTION(creator,
                "How can that happen if we have nodes to construct frames for?");
   for (uint32_t i=0; i < count; i++) {
     nsIContent* content = newAnonymousItems[i].mContent;
     NS_ASSERTION(content, "null anonymous content?");
     NS_ASSERTION(!newAnonymousItems[i].mStyleContext, "Unexpected style context");
     NS_ASSERTION(newAnonymousItems[i].mChildren.IsEmpty(),
                  "This method is not currently used with frames that implement "
                  "nsIAnonymousContentCreator::CreateAnonymousContent to "
                  "output a list where the items have their own children");
     nsIFrame* newFrame = creator->CreateFrameFor(content);
     if (newFrame) {
       NS_ASSERTION(content->GetPrimaryFrame(),
                    "Content must have a primary frame now");
       newFrame->AddStateBits(NS_FRAME_ANONYMOUSCONTENTCREATOR_CONTENT);
       aChildItems.AddChild(newFrame);
     } else {
       FrameConstructionItemList items;
       {
         // Skip flex item style-fixup during our AddFrameConstructionItems() call:
         TreeMatchContext::AutoFlexItemStyleFixupSkipper
           flexItemStyleFixupSkipper(aState.mTreeMatchContext);
         AddFrameConstructionItems(aState, content, true, aParentFrame, items);
       }
       ConstructFramesFromItemList(aState, items, aParentFrame, aChildItems);
     }
   }
   return NS_OK;
 }
 static void
 SetFlagsOnSubtree(nsIContent *aNode, uintptr_t aFlagsToSet)
 {
 #ifdef DEBUG
   // Make sure that the node passed to us doesn't have any XBL children
   {
     FlattenedChildIterator iter(aNode);
     NS_ASSERTION(!iter.XBLInvolved() || !iter.GetNextChild(),
                  "The node should not have any XBL children");
   }
 #endif
   // Set the flag on the node itself
   aNode->SetFlags(aFlagsToSet);
   // Set the flag on all of its children recursively
   uint32_t count;
   nsIContent * const *children = aNode->GetChildArray(&count);
   for (uint32_t index = 0; index < count; ++index) {
     SetFlagsOnSubtree(children[index], aFlagsToSet);
   }
 }
 /**
  * This function takes a tree of nsIAnonymousContentCreator::ContentInfo
  * objects where the nsIContent nodes have just been created, and appends the
  * nsIContent children in the tree to their parent. The leaf nsIContent objects
  * are appended first to minimize the number of notifications that are sent
  * out (i.e. by appending as many descendants as posible while their parent is
  * not yet in the document tree).
  *
  * This function is used simply as a convenience so that implementations of
  * nsIAnonymousContentCreator::CreateAnonymousContent don't all have to have
  * their own code to connect the elements that they create.
  */
 static void
 ConnectAnonymousTreeDescendants(nsIContent* aParent,
                                 nsTArray<nsIAnonymousContentCreator::ContentInfo>& aContent)
 {
   uint32_t count = aContent.Length();
   for (uint32_t i=0; i < count; i++) {
     nsIContent* content = aContent[i].mContent;
     NS_ASSERTION(content, "null anonymous content?");
     ConnectAnonymousTreeDescendants(content, aContent[i].mChildren);
     aParent->AppendChildTo(content, false);
   }
 }
 nsresult
 nsCSSFrameConstructor::GetAnonymousContent(nsIContent* aParent,
                                            nsIFrame* aParentFrame,
                                            nsTArray<nsIAnonymousContentCreator::ContentInfo>& aContent)
 {
   nsIAnonymousContentCreator* creator = do_QueryFrame(aParentFrame);
   if (!creator)
     return NS_OK;
   nsresult rv = creator->CreateAnonymousContent(aContent);
   NS_ENSURE_SUCCESS(rv, rv);
   uint32_t count = aContent.Length();
   for (uint32_t i=0; i < count; i++) {
     // get our child's content and set its parent to our content
     nsIContent* content = aContent[i].mContent;
     NS_ASSERTION(content, "null anonymous content?");
     // least-surprise CSS binding until we do the SVG specified
     // cascading rules for <svg:use> - bug 265894
     if (aParentFrame->GetType() == nsGkAtoms::svgUseFrame) {
       content->SetFlags(NODE_IS_ANONYMOUS_ROOT);
     } else {
       content->SetIsNativeAnonymousRoot();
     }
     ConnectAnonymousTreeDescendants(content, aContent[i].mChildren);
     bool anonContentIsEditable = content->HasFlag(NODE_IS_EDITABLE);
     rv = content->BindToTree(mDocument, aParent, aParent, true);
     // If the anonymous content creator requested that the content should be
     // editable, honor its request.
     // We need to set the flag on the whole subtree, because existing
     // children's flags have already been set as part of the BindToTree operation.
     if (anonContentIsEditable) {
       NS_ASSERTION(aParentFrame->GetType() == nsGkAtoms::textInputFrame,
                    "We only expect this for anonymous content under a text control frame");
       SetFlagsOnSubtree(content, NODE_IS_EDITABLE);
     }
     if (NS_FAILED(rv)) {
       content->UnbindFromTree();
       return rv;
     }
   }
   return NS_OK;
 }
 static
 bool IsXULDisplayType(const nsStyleDisplay* aDisplay)
 {
   return (aDisplay->mDisplay == NS_STYLE_DISPLAY_INLINE_BOX ||
 #ifdef MOZ_XUL
           aDisplay->mDisplay == NS_STYLE_DISPLAY_INLINE_XUL_GRID ||
           aDisplay->mDisplay == NS_STYLE_DISPLAY_INLINE_STACK ||
 #endif
           aDisplay->mDisplay == NS_STYLE_DISPLAY_BOX
 #ifdef MOZ_XUL
           || aDisplay->mDisplay == NS_STYLE_DISPLAY_XUL_GRID ||
           aDisplay->mDisplay == NS_STYLE_DISPLAY_STACK ||
           aDisplay->mDisplay == NS_STYLE_DISPLAY_XUL_GRID_GROUP ||
           aDisplay->mDisplay == NS_STYLE_DISPLAY_XUL_GRID_LINE ||
           aDisplay->mDisplay == NS_STYLE_DISPLAY_DECK ||
           aDisplay->mDisplay == NS_STYLE_DISPLAY_POPUP ||
           aDisplay->mDisplay == NS_STYLE_DISPLAY_GROUPBOX
 #endif
           );
 }
 // XUL frames are not allowed to be out of flow.
 #define SIMPLE_XUL_FCDATA(_func)                                        \
   FCDATA_DECL(FCDATA_DISALLOW_OUT_OF_FLOW | FCDATA_SKIP_ABSPOS_PUSH,    \
               _func)
 #define SCROLLABLE_XUL_FCDATA(_func)                                    \
   FCDATA_DECL(FCDATA_DISALLOW_OUT_OF_FLOW | FCDATA_SKIP_ABSPOS_PUSH |   \
               FCDATA_MAY_NEED_SCROLLFRAME, _func)
 // .. but we allow some XUL frames to be _containers_ for out-of-flow content
 // (This is the same as SCROLLABLE_XUL_FCDATA, but w/o FCDATA_SKIP_ABSPOS_PUSH)
 #define SCROLLABLE_ABSPOS_CONTAINER_XUL_FCDATA(_func)                   \
   FCDATA_DECL(FCDATA_DISALLOW_OUT_OF_FLOW |                             \
               FCDATA_MAY_NEED_SCROLLFRAME, _func)
 #define SIMPLE_XUL_CREATE(_tag, _func)            \
   { &nsGkAtoms::_tag, SIMPLE_XUL_FCDATA(_func) }
 #define SCROLLABLE_XUL_CREATE(_tag, _func)            \
   { &nsGkAtoms::_tag, SCROLLABLE_XUL_FCDATA(_func) }
 #define SIMPLE_XUL_INT_CREATE(_int, _func)      \
   { _int, SIMPLE_XUL_FCDATA(_func) }
 #define SCROLLABLE_XUL_INT_CREATE(_int, _func)                          \
   { _int, SCROLLABLE_XUL_FCDATA(_func) }
 #define SCROLLABLE_ABSPOS_CONTAINER_XUL_INT_CREATE(_int, _func)         \
   { _int, SCROLLABLE_ABSPOS_CONTAINER_XUL_FCDATA(_func) }
 static
 nsIFrame* NS_NewGridBoxFrame(nsIPresShell* aPresShell,
                              nsStyleContext* aStyleContext)
 {
   nsCOMPtr<nsBoxLayout> layout;
   NS_NewGridLayout2(aPresShell, getter_AddRefs(layout));
   return NS_NewBoxFrame(aPresShell, aStyleContext, false, layout);
 }
 /* static */
 const nsCSSFrameConstructor::FrameConstructionData*
 nsCSSFrameConstructor::FindXULTagData(Element* aElement,
                                       nsIAtom* aTag,
                                       int32_t aNameSpaceID,
                                       nsStyleContext* aStyleContext)
 {
   if (aNameSpaceID != kNameSpaceID_XUL) {
     return nullptr;
   }
   static const FrameConstructionDataByTag sXULTagData[] = {
 #ifdef MOZ_XUL
     SCROLLABLE_XUL_CREATE(button, NS_NewButtonBoxFrame),
     SCROLLABLE_XUL_CREATE(checkbox, NS_NewButtonBoxFrame),
     SCROLLABLE_XUL_CREATE(radio, NS_NewButtonBoxFrame),
     SCROLLABLE_XUL_CREATE(autorepeatbutton, NS_NewAutoRepeatBoxFrame),
     SCROLLABLE_XUL_CREATE(titlebar, NS_NewTitleBarFrame),
     SCROLLABLE_XUL_CREATE(resizer, NS_NewResizerFrame),
     SIMPLE_XUL_CREATE(image, NS_NewImageBoxFrame),
     SIMPLE_XUL_CREATE(spring, NS_NewLeafBoxFrame),
     SIMPLE_XUL_CREATE(spacer, NS_NewLeafBoxFrame),
     SIMPLE_XUL_CREATE(treechildren, NS_NewTreeBodyFrame),
     SIMPLE_XUL_CREATE(treecol, NS_NewTreeColFrame),
     SIMPLE_XUL_CREATE(text, NS_NewTextBoxFrame),
     SIMPLE_TAG_CHAIN(label, nsCSSFrameConstructor::FindXULLabelData),
     SIMPLE_TAG_CHAIN(description, nsCSSFrameConstructor::FindXULDescriptionData),
     SIMPLE_XUL_CREATE(menu, NS_NewMenuFrame),
     SIMPLE_XUL_CREATE(menubutton, NS_NewMenuFrame),
     SIMPLE_XUL_CREATE(menuitem, NS_NewMenuItemFrame),
 #ifdef XP_MACOSX
     SIMPLE_TAG_CHAIN(menubar, nsCSSFrameConstructor::FindXULMenubarData),
 #else
     SIMPLE_XUL_CREATE(menubar, NS_NewMenuBarFrame),
 #endif /* XP_MACOSX */
     SIMPLE_TAG_CHAIN(popupgroup, nsCSSFrameConstructor::FindPopupGroupData),
     SIMPLE_XUL_CREATE(iframe, NS_NewSubDocumentFrame),
     SIMPLE_XUL_CREATE(editor, NS_NewSubDocumentFrame),
     SIMPLE_XUL_CREATE(browser, NS_NewSubDocumentFrame),
     SIMPLE_XUL_CREATE(progressmeter, NS_NewProgressMeterFrame),
     SIMPLE_XUL_CREATE(splitter, NS_NewSplitterFrame),
     SIMPLE_TAG_CHAIN(listboxbody,
                      nsCSSFrameConstructor::FindXULListBoxBodyData),
     SIMPLE_TAG_CHAIN(listitem, nsCSSFrameConstructor::FindXULListItemData),
 #endif /* MOZ_XUL */
     SIMPLE_XUL_CREATE(slider, NS_NewSliderFrame),
     SIMPLE_XUL_CREATE(scrollbar, NS_NewScrollbarFrame),
     SIMPLE_XUL_CREATE(scrollbarbutton, NS_NewScrollbarButtonFrame)
 };
   return FindDataByTag(aTag, aElement, aStyleContext, sXULTagData,
                        ArrayLength(sXULTagData));
 }
 #ifdef MOZ_XUL
 /* static */
 const nsCSSFrameConstructor::FrameConstructionData*
 nsCSSFrameConstructor::FindPopupGroupData(Element* aElement,
                                           nsStyleContext* /* unused */)
 {
   if (!aElement->IsRootOfNativeAnonymousSubtree()) {
     return nullptr;
   }
   static const FrameConstructionData sPopupSetData =
     SIMPLE_XUL_FCDATA(NS_NewPopupSetFrame);
   return &sPopupSetData;
 }
 /* static */
 const nsCSSFrameConstructor::FrameConstructionData
 nsCSSFrameConstructor::sXULTextBoxData = SIMPLE_XUL_FCDATA(NS_NewTextBoxFrame);
 /* static */
 const nsCSSFrameConstructor::FrameConstructionData*
 nsCSSFrameConstructor::FindXULLabelData(Element* aElement,
                                         nsStyleContext* /* unused */)
 {
   if (aElement->HasAttr(kNameSpaceID_None, nsGkAtoms::value)) {
     return &sXULTextBoxData;
   }
   static const FrameConstructionData sLabelData =
     SIMPLE_XUL_FCDATA(NS_NewXULLabelFrame);
   return &sLabelData;
 }
 static nsIFrame*
 NS_NewXULDescriptionFrame(nsIPresShell* aPresShell, nsStyleContext *aContext)
 {
   // XXXbz do we really need to set those flags?  If the parent is not
   // a block we'll get them anyway, and if it is, do we want them?
   return NS_NewBlockFrame(aPresShell, aContext,
                           NS_BLOCK_FLOAT_MGR | NS_BLOCK_MARGIN_ROOT);
 }
 /* static */
 const nsCSSFrameConstructor::FrameConstructionData*
 nsCSSFrameConstructor::FindXULDescriptionData(Element* aElement,
                                               nsStyleContext* /* unused */)
 {
   if (aElement->HasAttr(kNameSpaceID_None, nsGkAtoms::value)) {
     return &sXULTextBoxData;
   }
   static const FrameConstructionData sDescriptionData =
     SIMPLE_XUL_FCDATA(NS_NewXULDescriptionFrame);
   return &sDescriptionData;
 }
 #ifdef XP_MACOSX
 /* static */
 const nsCSSFrameConstructor::FrameConstructionData*
 nsCSSFrameConstructor::FindXULMenubarData(Element* aElement,
                                           nsStyleContext* aStyleContext)
 {
   nsCOMPtr<nsIDocShell> treeItem =
     aStyleContext->PresContext()->GetDocShell();
   if (treeItem && nsIDocShellTreeItem::typeChrome == treeItem->ItemType()) {
     nsCOMPtr<nsIDocShellTreeItem> parent;
     treeItem->GetParent(getter_AddRefs(parent));
     if (!parent) {
       // This is the root.  Suppress the menubar, since on Mac
       // window menus are not attached to the window.
       static const FrameConstructionData sSuppressData = SUPPRESS_FCDATA();
       return &sSuppressData;
     }
   }
   static const FrameConstructionData sMenubarData =
     SIMPLE_XUL_FCDATA(NS_NewMenuBarFrame);
   return &sMenubarData;
 }
 #endif /* XP_MACOSX */
 /* static */
 const nsCSSFrameConstructor::FrameConstructionData*
 nsCSSFrameConstructor::FindXULListBoxBodyData(Element* aElement,
                                               nsStyleContext* aStyleContext)
 {
   if (aStyleContext->StyleDisplay()->mDisplay !=
         NS_STYLE_DISPLAY_XUL_GRID_GROUP) {
     return nullptr;
   }
   static const FrameConstructionData sListBoxBodyData =
     SCROLLABLE_XUL_FCDATA(NS_NewListBoxBodyFrame);
   return &sListBoxBodyData;
 }
 /* static */
 const nsCSSFrameConstructor::FrameConstructionData*
 nsCSSFrameConstructor::FindXULListItemData(Element* aElement,
                                            nsStyleContext* aStyleContext)
 {
   if (aStyleContext->StyleDisplay()->mDisplay !=
         NS_STYLE_DISPLAY_XUL_GRID_LINE) {
     return nullptr;
   }
   static const FrameConstructionData sListItemData =
     SCROLLABLE_XUL_FCDATA(NS_NewListItemFrame);
   return &sListItemData;
 }
 #endif /* MOZ_XUL */
 /* static */
 const nsCSSFrameConstructor::FrameConstructionData*
 nsCSSFrameConstructor::FindXULDisplayData(const nsStyleDisplay* aDisplay,
                                           Element* aElement,
                                           nsStyleContext* aStyleContext)
 {
   static const FrameConstructionDataByInt sXULDisplayData[] = {
     SCROLLABLE_ABSPOS_CONTAINER_XUL_INT_CREATE(NS_STYLE_DISPLAY_INLINE_BOX,
                                                NS_NewBoxFrame),
     SCROLLABLE_ABSPOS_CONTAINER_XUL_INT_CREATE(NS_STYLE_DISPLAY_BOX,
                                                NS_NewBoxFrame),
 #ifdef MOZ_XUL
     SCROLLABLE_XUL_INT_CREATE(NS_STYLE_DISPLAY_INLINE_XUL_GRID, NS_NewGridBoxFrame),
     SCROLLABLE_XUL_INT_CREATE(NS_STYLE_DISPLAY_XUL_GRID, NS_NewGridBoxFrame),
     SCROLLABLE_XUL_INT_CREATE(NS_STYLE_DISPLAY_XUL_GRID_GROUP,
                               NS_NewGridRowGroupFrame),
     SCROLLABLE_XUL_INT_CREATE(NS_STYLE_DISPLAY_XUL_GRID_LINE,
                               NS_NewGridRowLeafFrame),
     SIMPLE_XUL_INT_CREATE(NS_STYLE_DISPLAY_DECK, NS_NewDeckFrame),
     SCROLLABLE_XUL_INT_CREATE(NS_STYLE_DISPLAY_GROUPBOX, NS_NewGroupBoxFrame),
     SCROLLABLE_XUL_INT_CREATE(NS_STYLE_DISPLAY_INLINE_STACK, NS_NewStackFrame),
     SCROLLABLE_XUL_INT_CREATE(NS_STYLE_DISPLAY_STACK, NS_NewStackFrame),
     { NS_STYLE_DISPLAY_POPUP,
       FCDATA_DECL(FCDATA_DISALLOW_OUT_OF_FLOW | FCDATA_IS_POPUP |
                   FCDATA_SKIP_ABSPOS_PUSH, NS_NewMenuPopupFrame) }
 #endif /* MOZ_XUL */
   };
   // Processing by display here:
   return FindDataByInt(aDisplay->mDisplay, aElement, aStyleContext,
                        sXULDisplayData, ArrayLength(sXULDisplayData));
 }
 already_AddRefed<nsStyleContext>
 nsCSSFrameConstructor::BeginBuildingScrollFrame(nsFrameConstructorState& aState,
                                                 nsIContent*              aContent,
                                                 nsStyleContext*          aContentStyle,
                                                 nsIFrame*                aParentFrame,
                                                 nsIAtom*                 aScrolledPseudo,
                                                 bool                     aIsRoot,
                                                 nsIFrame*&               aNewFrame)
 {
   nsIFrame* gfxScrollFrame = aNewFrame;
   nsFrameItems anonymousItems;
   nsRefPtr<nsStyleContext> contentStyle = aContentStyle;
   if (!gfxScrollFrame) {
     // Build a XULScrollFrame when the child is a box, otherwise an
     // HTMLScrollFrame
     // XXXbz this is the lone remaining consumer of IsXULDisplayType.
     // I wonder whether we can eliminate that somehow.
     const nsStyleDisplay* displayStyle = aContentStyle->StyleDisplay();
     if (IsXULDisplayType(displayStyle)) {
       gfxScrollFrame = NS_NewXULScrollFrame(mPresShell, contentStyle, aIsRoot,
           displayStyle->mDisplay == NS_STYLE_DISPLAY_STACK ||
           displayStyle->mDisplay == NS_STYLE_DISPLAY_INLINE_STACK);
     } else {
       gfxScrollFrame = NS_NewHTMLScrollFrame(mPresShell, contentStyle, aIsRoot);
     }
     InitAndRestoreFrame(aState, aContent, aParentFrame, gfxScrollFrame);
   }
   // if there are any anonymous children for the scroll frame, create
   // frames for them.
   // Pass a null pending binding: we don't care how constructors for any of
   // this anonymous content order with anything else.  It's never been
   // consistent anyway.
   CreateAnonymousFrames(aState, aContent, gfxScrollFrame, nullptr,
                         anonymousItems);
   aNewFrame = gfxScrollFrame;
   // we used the style that was passed in. So resolve another one.
   nsStyleSet *styleSet = mPresShell->StyleSet();
   nsRefPtr<nsStyleContext> scrolledChildStyle =
     styleSet->ResolveAnonymousBoxStyle(aScrolledPseudo, contentStyle);
   if (gfxScrollFrame) {
      gfxScrollFrame->SetInitialChildList(kPrincipalList, anonymousItems);
   }
   return scrolledChildStyle.forget();
 }
 void
 nsCSSFrameConstructor::FinishBuildingScrollFrame(nsIFrame* aScrollFrame,
                                                  nsIFrame* aScrolledFrame)
 {
   nsFrameList scrolled(aScrolledFrame, aScrolledFrame);
   aScrollFrame->AppendFrames(kPrincipalList, scrolled);
 }
 /**
  * Called to wrap a gfx scrollframe around a frame. The hierarchy will look like this
  *
  * ------- for gfx scrollbars ------
  *
  *
  *            ScrollFrame
  *                 ^
  *                 |
  *               Frame (scrolled frame you passed in)
  *
  *
  *-----------------------------------
  * LEGEND:
  *
  * ScrollFrame: This is a frame that manages gfx cross platform frame based scrollbars.
  *
  * @param aContent the content node of the child to wrap.
  * @param aScrolledFrame The frame of the content to wrap. This should not be
  *                    Initialized. This method will initialize it with a scrolled pseudo
  *                    and no nsIContent. The content will be attached to the scrollframe
  *                    returned.
  * @param aContentStyle the style context that has already been resolved for the content being passed in.
  *
  * @param aParentFrame The parent to attach the scroll frame to
  *
  * @param aNewFrame The new scrollframe or gfx scrollframe that we create. It will contain the
  *                  scrolled frame you passed in. (returned)
  *                  If this is not null, we'll just use it
  * @param aScrolledContentStyle the style that was resolved for the scrolled frame. (returned)
  */
 nsresult
 nsCSSFrameConstructor::BuildScrollFrame(nsFrameConstructorState& aState,
                                         nsIContent*              aContent,
                                         nsStyleContext*          aContentStyle,
                                         nsIFrame*                aScrolledFrame,
                                         nsIFrame*                aParentFrame,
                                         nsIFrame*&               aNewFrame)
 {
     nsRefPtr<nsStyleContext> scrolledContentStyle =
       BeginBuildingScrollFrame(aState, aContent, aContentStyle, aParentFrame,
                                nsCSSAnonBoxes::scrolledContent,
                                false, aNewFrame);
     aScrolledFrame->SetStyleContextWithoutNotification(scrolledContentStyle);
     InitAndRestoreFrame(aState, aContent, aNewFrame, aScrolledFrame);
     FinishBuildingScrollFrame(aNewFrame, aScrolledFrame);
     return NS_OK;
 }
 const nsCSSFrameConstructor::FrameConstructionData*
 nsCSSFrameConstructor::FindDisplayData(const nsStyleDisplay* aDisplay,
                                        Element* aElement,
                                        nsIFrame* aParentFrame,
                                        nsStyleContext* aStyleContext)
 {
   PR_STATIC_ASSERT(eParentTypeCount < (1 << (32 - FCDATA_PARENT_TYPE_OFFSET)));
   // The style system ensures that floated and positioned frames are
   // block-level.
   NS_ASSERTION(!(aDisplay->IsFloatingStyle() ||
                  aDisplay->IsAbsolutelyPositionedStyle()) ||
                aDisplay->IsBlockOutsideStyle(),
                "Style system did not apply CSS2.1 section 9.7 fixups");
   // If this is "body", try propagating its scroll style to the viewport
   // Note that we need to do this even if the body is NOT scrollable;
   // it might have dynamically changed from scrollable to not scrollable,
   // and that might need to be propagated.
   // XXXbz is this the right place to do this?  If this code moves,
   // make this function static.
   bool propagatedScrollToViewport = false;
   if (aElement->IsHTML(nsGkAtoms::body)) {
     propagatedScrollToViewport =
       PropagateScrollToViewport() == aElement;
   }
   NS_ASSERTION(!propagatedScrollToViewport ||
                !mPresShell->GetPresContext()->IsPaginated(),
                "Shouldn't propagate scroll in paginated contexts");
   // If the frame is a block-level frame and is scrollable, then wrap it in a
   // scroll frame.
   // XXX Ignore tables for the time being
   // XXXbz it would be nice to combine this with the other block
   // case... Think about how do do this?
   if (aDisplay->IsBlockInsideStyle() &&
       aDisplay->IsScrollableOverflow() &&
       !propagatedScrollToViewport) {
     // Except we don't want to do that for paginated contexts for
     // frames that are block-outside and aren't frames for native
     // anonymous stuff.
     if (mPresShell->GetPresContext()->IsPaginated() &&
         aDisplay->IsBlockOutsideStyle() &&
         !aElement->IsInNativeAnonymousSubtree()) {
       static const FrameConstructionData sForcedNonScrollableBlockData =
         FULL_CTOR_FCDATA(FCDATA_FORCED_NON_SCROLLABLE_BLOCK,
                          &nsCSSFrameConstructor::ConstructNonScrollableBlock);
       return &sForcedNonScrollableBlockData;
     }
     static const FrameConstructionData sScrollableBlockData =
       FULL_CTOR_FCDATA(0, &nsCSSFrameConstructor::ConstructScrollableBlock);
     return &sScrollableBlockData;
   }
   // Handle various non-scrollable blocks
   if (aDisplay->IsBlockInsideStyle()) {
     static const FrameConstructionData sNonScrollableBlockData =
       FULL_CTOR_FCDATA(0, &nsCSSFrameConstructor::ConstructNonScrollableBlock);
     return &sNonScrollableBlockData;
   }
   static const FrameConstructionDataByInt sDisplayData[] = {
     // To keep the hash table small don't add inline frames (they're
     // typically things like FONT and B), because we can quickly
     // find them if we need to.
     // XXXbz the "quickly" part is a bald-faced lie!
     { NS_STYLE_DISPLAY_INLINE,
       FULL_CTOR_FCDATA(FCDATA_IS_INLINE | FCDATA_IS_LINE_PARTICIPANT,
                        &nsCSSFrameConstructor::ConstructInline) },
     { NS_STYLE_DISPLAY_FLEX,
       FCDATA_DECL(FCDATA_MAY_NEED_SCROLLFRAME, NS_NewFlexContainerFrame) },
     { NS_STYLE_DISPLAY_INLINE_FLEX,
       FCDATA_DECL(FCDATA_MAY_NEED_SCROLLFRAME, NS_NewFlexContainerFrame) },
     { NS_STYLE_DISPLAY_GRID,
       FCDATA_DECL(FCDATA_MAY_NEED_SCROLLFRAME, NS_NewGridContainerFrame) },
     { NS_STYLE_DISPLAY_INLINE_GRID,
       FCDATA_DECL(FCDATA_MAY_NEED_SCROLLFRAME, NS_NewGridContainerFrame) },
     { NS_STYLE_DISPLAY_TABLE,
       FULL_CTOR_FCDATA(0, &nsCSSFrameConstructor::ConstructTable) },
     { NS_STYLE_DISPLAY_INLINE_TABLE,
       FULL_CTOR_FCDATA(0, &nsCSSFrameConstructor::ConstructTable) },
     // NOTE: In the unlikely event that we add another table-part here that has
     // a desired-parent-type (& hence triggers table fixup), we'll need to also
     // update the flexbox chunk in nsStyleContext::ApplyStyleFixups().
     { NS_STYLE_DISPLAY_TABLE_CAPTION,
       FCDATA_DECL(FCDATA_IS_TABLE_PART | FCDATA_ALLOW_BLOCK_STYLES |
                   FCDATA_DISALLOW_OUT_OF_FLOW | FCDATA_SKIP_ABSPOS_PUSH |
                   FCDATA_DESIRED_PARENT_TYPE_TO_BITS(eTypeTable),
                   NS_NewTableCaptionFrame) },
     { NS_STYLE_DISPLAY_TABLE_ROW_GROUP,
       FULL_CTOR_FCDATA(FCDATA_IS_TABLE_PART |
                        FCDATA_DESIRED_PARENT_TYPE_TO_BITS(eTypeTable),
                        &nsCSSFrameConstructor::ConstructTableRowOrRowGroup) },
     { NS_STYLE_DISPLAY_TABLE_HEADER_GROUP,
       FULL_CTOR_FCDATA(FCDATA_IS_TABLE_PART |
                        FCDATA_DESIRED_PARENT_TYPE_TO_BITS(eTypeTable),
                        &nsCSSFrameConstructor::ConstructTableRowOrRowGroup) },
     { NS_STYLE_DISPLAY_TABLE_FOOTER_GROUP,
       FULL_CTOR_FCDATA(FCDATA_IS_TABLE_PART |
                        FCDATA_DESIRED_PARENT_TYPE_TO_BITS(eTypeTable),
                        &nsCSSFrameConstructor::ConstructTableRowOrRowGroup) },
     { NS_STYLE_DISPLAY_TABLE_COLUMN_GROUP,
       FCDATA_DECL(FCDATA_IS_TABLE_PART | FCDATA_DISALLOW_OUT_OF_FLOW |
                   FCDATA_SKIP_ABSPOS_PUSH |
                   FCDATA_DESIRED_PARENT_TYPE_TO_BITS(eTypeTable),
                   NS_NewTableColGroupFrame) },
     { NS_STYLE_DISPLAY_TABLE_COLUMN,
       FULL_CTOR_FCDATA(FCDATA_IS_TABLE_PART |
                        FCDATA_DESIRED_PARENT_TYPE_TO_BITS(eTypeColGroup),
                        &nsCSSFrameConstructor::ConstructTableCol) },
     { NS_STYLE_DISPLAY_TABLE_ROW,
       FULL_CTOR_FCDATA(FCDATA_IS_TABLE_PART |
                        FCDATA_DESIRED_PARENT_TYPE_TO_BITS(eTypeRowGroup),
                        &nsCSSFrameConstructor::ConstructTableRowOrRowGroup) },
     { NS_STYLE_DISPLAY_TABLE_CELL,
       FULL_CTOR_FCDATA(FCDATA_IS_TABLE_PART |
                        FCDATA_DESIRED_PARENT_TYPE_TO_BITS(eTypeRow),
                        &nsCSSFrameConstructor::ConstructTableCell) }
   };
   return FindDataByInt(aDisplay->mDisplay,
                        aElement, aStyleContext, sDisplayData,
                        ArrayLength(sDisplayData));
 }
 nsIFrame*
 nsCSSFrameConstructor::ConstructScrollableBlock(nsFrameConstructorState& aState,
                                                 FrameConstructionItem&   aItem,
                                                 nsIFrame*                aParentFrame,
                                                 const nsStyleDisplay*    aDisplay,
                                                 nsFrameItems&            aFrameItems)
 {
   nsIContent* const content = aItem.mContent;
   nsStyleContext* const styleContext = aItem.mStyleContext;
   nsIFrame* newFrame = nullptr;
   nsRefPtr<nsStyleContext> scrolledContentStyle
     = BeginBuildingScrollFrame(aState, content, styleContext,
                                aState.GetGeometricParent(aDisplay, aParentFrame),
                                nsCSSAnonBoxes::scrolledContent,
                                false, newFrame);
   // Create our block frame
   // pass a temporary stylecontext, the correct one will be set later
   nsIFrame* scrolledFrame =
     NS_NewBlockFormattingContext(mPresShell, styleContext);
   // Make sure to AddChild before we call ConstructBlock so that we
   // end up before our descendants in fixed-pos lists as needed.
   aState.AddChild(newFrame, aFrameItems, content, styleContext, aParentFrame);
   nsFrameItems blockItem;
   ConstructBlock(aState, scrolledContentStyle->StyleDisplay(), content,
                  newFrame, newFrame, scrolledContentStyle,
                  &scrolledFrame, blockItem,
                  aDisplay->IsPositioned(newFrame) ? newFrame : nullptr,
                  aItem.mPendingBinding);
   NS_ASSERTION(blockItem.FirstChild() == scrolledFrame,
                "Scrollframe's frameItems should be exactly the scrolled frame");
   FinishBuildingScrollFrame(newFrame, scrolledFrame);
   return newFrame;
 }
 nsIFrame*
 nsCSSFrameConstructor::ConstructNonScrollableBlock(nsFrameConstructorState& aState,
                                                    FrameConstructionItem&   aItem,
                                                    nsIFrame*                aParentFrame,
                                                    const nsStyleDisplay*    aDisplay,
                                                    nsFrameItems&            aFrameItems)
 {
   nsStyleContext* const styleContext = aItem.mStyleContext;
   // We want a block formatting context root in paginated contexts for
   // every block that would be scrollable in a non-paginated context.
   // We mark our blocks with a bit here if this condition is true, so
   // we can check it later in nsFrame::ApplyPaginatedOverflowClipping.
   bool clipPaginatedOverflow =
     (aItem.mFCData->mBits & FCDATA_FORCED_NON_SCROLLABLE_BLOCK) != 0;
   nsIFrame* newFrame;
   if ((aDisplay->IsAbsolutelyPositionedStyle() ||
        aDisplay->IsFloatingStyle() ||
        NS_STYLE_DISPLAY_INLINE_BLOCK == aDisplay->mDisplay ||
        clipPaginatedOverflow) &&
       !aParentFrame->IsSVGText()) {
     newFrame = NS_NewBlockFormattingContext(mPresShell, styleContext);
     if (clipPaginatedOverflow) {
       newFrame->AddStateBits(NS_BLOCK_CLIP_PAGINATED_OVERFLOW);
     }
   } else {
     newFrame = NS_NewBlockFrame(mPresShell, styleContext);
   }
   ConstructBlock(aState, aDisplay, aItem.mContent,
                  aState.GetGeometricParent(aDisplay, aParentFrame),
                  aParentFrame, styleContext, &newFrame,
                  aFrameItems,
                  aDisplay->IsPositioned(newFrame) ? newFrame : nullptr,
                  aItem.mPendingBinding);
   return newFrame;
 }
 void
 nsCSSFrameConstructor::InitAndRestoreFrame(const nsFrameConstructorState& aState,
                                            nsIContent*              aContent,
                                            nsIFrame*                aParentFrame,
                                            nsIFrame*                aNewFrame,
                                            bool                     aAllowCounters)
 {
   NS_PRECONDITION(mUpdateCount != 0,
                   "Should be in an update while creating frames");
   MOZ_ASSERT(aNewFrame, "Null frame cannot be initialized");
   // Initialize the frame
   aNewFrame->Init(aContent, aParentFrame, nullptr);
   aNewFrame->AddStateBits(aState.mAdditionalStateBits);
   if (aState.mFrameState) {
     // Restore frame state for just the newly created frame.
     RestoreFrameStateFor(aNewFrame, aState.mFrameState);
   }
   if (aAllowCounters &&
       mCounterManager.AddCounterResetsAndIncrements(aNewFrame)) {
     CountersDirty();
   }
 }
 already_AddRefed<nsStyleContext>
 nsCSSFrameConstructor::ResolveStyleContext(nsIFrame*         aParentFrame,
                                            nsIContent*       aContent,
                                            nsFrameConstructorState* aState)
 {
   nsStyleContext* parentStyleContext = nullptr;
   NS_ASSERTION(aContent->GetParent(), "Must have parent here");
   aParentFrame = nsFrame::CorrectStyleParentFrame(aParentFrame, nullptr);
   if (aParentFrame) {
     // Resolve the style context based on the content object and the parent
     // style context
     parentStyleContext = aParentFrame->StyleContext();
   } else {
     // Perhaps aParentFrame is a canvasFrame and we're replicating
     // fixed-pos frames.
     // XXX should we create a way to tell ConstructFrame which style
     // context to use, and pass it the style context for the
     // previous page's fixed-pos frame?
   }
   return ResolveStyleContext(parentStyleContext, aContent, aState);
 }
 already_AddRefed<nsStyleContext>
 nsCSSFrameConstructor::ResolveStyleContext(nsStyleContext* aParentStyleContext,
                                            nsIContent* aContent,
                                            nsFrameConstructorState* aState)
 {
   nsStyleSet *styleSet = mPresShell->StyleSet();
   aContent->OwnerDoc()->FlushPendingLinkUpdates();
   if (aContent->IsElement()) {
     if (aState) {
       return styleSet->ResolveStyleFor(aContent->AsElement(),
                                        aParentStyleContext,
                                        aState->mTreeMatchContext);
     }
     return styleSet->ResolveStyleFor(aContent->AsElement(), aParentStyleContext);
   }
   NS_ASSERTION(aContent->IsNodeOfType(nsINode::eTEXT),
                "shouldn't waste time creating style contexts for "
                "comments and processing instructions");
   return styleSet->ResolveStyleForNonElement(aParentStyleContext);
 }
 // MathML Mod - RBS
 void
 nsCSSFrameConstructor::FlushAccumulatedBlock(nsFrameConstructorState& aState,
                                              nsIContent* aContent,
                                              nsIFrame* aParentFrame,
                                              nsFrameItems& aBlockItems,
                                              nsFrameItems& aNewItems)
 {
   if (aBlockItems.IsEmpty()) {
     // Nothing to do
     return;
   }
   nsIAtom* anonPseudo = nsCSSAnonBoxes::mozMathMLAnonymousBlock;
   nsStyleContext* parentContext =
     nsFrame::CorrectStyleParentFrame(aParentFrame,
                                      anonPseudo)->StyleContext();
   nsStyleSet* styleSet = mPresShell->StyleSet();
   nsRefPtr<nsStyleContext> blockContext;
   blockContext = styleSet->
     ResolveAnonymousBoxStyle(anonPseudo, parentContext);
   // then, create a block frame that will wrap the child frames. Make it a
   // MathML frame so that Get(Absolute/Float)ContainingBlockFor know that this
   // is not a suitable block.
   nsIFrame* blockFrame =
       NS_NewMathMLmathBlockFrame(mPresShell, blockContext,
                                  NS_BLOCK_FLOAT_MGR | NS_BLOCK_MARGIN_ROOT);
   InitAndRestoreFrame(aState, aContent, aParentFrame, blockFrame);
   ReparentFrames(this, blockFrame, aBlockItems);
   // abs-pos and floats are disabled in MathML children so we don't have to
   // worry about messing up those.
   blockFrame->SetInitialChildList(kPrincipalList, aBlockItems);
   NS_ASSERTION(aBlockItems.IsEmpty(), "What happened?");
   aBlockItems.Clear();
   aNewItems.AddChild(blockFrame);
 }
 // Only <math> elements can be floated or positioned.  All other MathML
 // should be in-flow.
 #define SIMPLE_MATHML_CREATE(_tag, _func)                               \
   { &nsGkAtoms::_tag,                                                   \
       FCDATA_DECL(FCDATA_DISALLOW_OUT_OF_FLOW |                         \
                   FCDATA_FORCE_NULL_ABSPOS_CONTAINER |                  \
                   FCDATA_WRAP_KIDS_IN_BLOCKS, _func) }
 /* static */
 const nsCSSFrameConstructor::FrameConstructionData*
 nsCSSFrameConstructor::FindMathMLData(Element* aElement,
                                       nsIAtom* aTag,
                                       int32_t aNameSpaceID,
                                       nsStyleContext* aStyleContext)
 {
   // Make sure that we remain confined in the MathML world
   if (aNameSpaceID != kNameSpaceID_MathML)
     return nullptr;
   // Handle <math> specially, because it sometimes produces inlines
   if (aTag == nsGkAtoms::math) {
     // This needs to match the test in EnsureBlockDisplay in
     // nsRuleNode.cpp.  Though the behavior here for the display:table
     // case is pretty weird...
     if (aStyleContext->StyleDisplay()->IsBlockOutsideStyle()) {
       static const FrameConstructionData sBlockMathData =
         FCDATA_DECL(FCDATA_FORCE_NULL_ABSPOS_CONTAINER |
                     FCDATA_WRAP_KIDS_IN_BLOCKS,
                     NS_CreateNewMathMLmathBlockFrame);
       return &sBlockMathData;
     }
     static const FrameConstructionData sInlineMathData =
       FCDATA_DECL(FCDATA_FORCE_NULL_ABSPOS_CONTAINER |
                   FCDATA_IS_LINE_PARTICIPANT |
                   FCDATA_WRAP_KIDS_IN_BLOCKS,
                   NS_NewMathMLmathInlineFrame);
     return &sInlineMathData;
   }
   static const FrameConstructionDataByTag sMathMLData[] = {
     SIMPLE_MATHML_CREATE(annotation_, NS_NewMathMLTokenFrame),
     SIMPLE_MATHML_CREATE(annotation_xml_, NS_NewMathMLmrowFrame),
     SIMPLE_MATHML_CREATE(mi_, NS_NewMathMLTokenFrame),
     SIMPLE_MATHML_CREATE(mn_, NS_NewMathMLTokenFrame),
     SIMPLE_MATHML_CREATE(ms_, NS_NewMathMLTokenFrame),
     SIMPLE_MATHML_CREATE(mtext_, NS_NewMathMLTokenFrame),
     SIMPLE_MATHML_CREATE(mo_, NS_NewMathMLmoFrame),
     SIMPLE_MATHML_CREATE(mfrac_, NS_NewMathMLmfracFrame),
     SIMPLE_MATHML_CREATE(msup_, NS_NewMathMLmmultiscriptsFrame),
     SIMPLE_MATHML_CREATE(msub_, NS_NewMathMLmmultiscriptsFrame),
     SIMPLE_MATHML_CREATE(msubsup_, NS_NewMathMLmmultiscriptsFrame),
     SIMPLE_MATHML_CREATE(munder_, NS_NewMathMLmunderoverFrame),
     SIMPLE_MATHML_CREATE(mover_, NS_NewMathMLmunderoverFrame),
     SIMPLE_MATHML_CREATE(munderover_, NS_NewMathMLmunderoverFrame),
     SIMPLE_MATHML_CREATE(mphantom_, NS_NewMathMLmphantomFrame),
     SIMPLE_MATHML_CREATE(mpadded_, NS_NewMathMLmpaddedFrame),
     SIMPLE_MATHML_CREATE(mspace_, NS_NewMathMLmspaceFrame),
     SIMPLE_MATHML_CREATE(none, NS_NewMathMLmspaceFrame),
     SIMPLE_MATHML_CREATE(mprescripts_, NS_NewMathMLmspaceFrame),
     SIMPLE_MATHML_CREATE(mfenced_, NS_NewMathMLmfencedFrame),
     SIMPLE_MATHML_CREATE(mmultiscripts_, NS_NewMathMLmmultiscriptsFrame),
     SIMPLE_MATHML_CREATE(mstyle_, NS_NewMathMLmrowFrame),
     SIMPLE_MATHML_CREATE(msqrt_, NS_NewMathMLmsqrtFrame),
     SIMPLE_MATHML_CREATE(mroot_, NS_NewMathMLmrootFrame),
     SIMPLE_MATHML_CREATE(maction_, NS_NewMathMLmactionFrame),
     SIMPLE_MATHML_CREATE(mrow_, NS_NewMathMLmrowFrame),
     SIMPLE_MATHML_CREATE(merror_, NS_NewMathMLmrowFrame),
     SIMPLE_MATHML_CREATE(menclose_, NS_NewMathMLmencloseFrame),
     SIMPLE_MATHML_CREATE(semantics_, NS_NewMathMLsemanticsFrame)
   };
   return FindDataByTag(aTag, aElement, aStyleContext, sMathMLData,
                        ArrayLength(sMathMLData));
 }
 nsIFrame*
 nsCSSFrameConstructor::ConstructFrameWithAnonymousChild(
                                    nsFrameConstructorState& aState,
                                    FrameConstructionItem&   aItem,
                                    nsIFrame*                aParentFrame,
                                    const nsStyleDisplay*    aDisplay,
                                    nsFrameItems&            aFrameItems,
                                    FrameCreationFunc        aConstructor,
                                    FrameCreationFunc        aInnerConstructor,
                                    nsICSSAnonBoxPseudo*     aInnerPseudo,
                                    bool                     aCandidateRootFrame)
 {
   nsIContent* const content = aItem.mContent;
   nsStyleContext* const styleContext = aItem.mStyleContext;
   // Create the outer frame:
   nsIFrame* newFrame = aConstructor(mPresShell, styleContext);
   InitAndRestoreFrame(aState, content,
                       aCandidateRootFrame ?
                         aState.GetGeometricParent(styleContext->StyleDisplay(),
                                                   aParentFrame) :
                         aParentFrame,
                       newFrame);
   // Create the pseudo SC for the anonymous wrapper child as a child of the SC:
   nsRefPtr<nsStyleContext> scForAnon;
   scForAnon = mPresShell->StyleSet()->
     ResolveAnonymousBoxStyle(aInnerPseudo, styleContext);
   // Create the anonymous inner wrapper frame
   nsIFrame* innerFrame = aInnerConstructor(mPresShell, scForAnon);
   InitAndRestoreFrame(aState, content, newFrame, innerFrame);
   // Put the newly created frames into the right child list
   SetInitialSingleChild(newFrame, innerFrame);
   aState.AddChild(newFrame, aFrameItems, content, styleContext, aParentFrame,
                   aCandidateRootFrame, aCandidateRootFrame);
   if (!mRootElementFrame && aCandidateRootFrame) {
     // The frame we're constructing will be the root element frame.
     // Set mRootElementFrame before processing children.
     mRootElementFrame = newFrame;
   }
   nsFrameItems childItems;
   // Process children
   NS_ASSERTION(aItem.mAnonChildren.IsEmpty(),
                "nsIAnonymousContentCreator::CreateAnonymousContent should not "
                "be implemented for frames for which we explicitly create an "
                "anonymous child to wrap its child frames");
   if (aItem.mFCData->mBits & FCDATA_USE_CHILD_ITEMS) {
     ConstructFramesFromItemList(aState, aItem.mChildItems,
                                 innerFrame, childItems);
   } else {
     ProcessChildren(aState, content, styleContext, innerFrame,
                     true, childItems, false, aItem.mPendingBinding);
   }
   // Set the inner wrapper frame's initial primary list
   innerFrame->SetInitialChildList(kPrincipalList, childItems);
   return newFrame;
 }
 nsIFrame*
 nsCSSFrameConstructor::ConstructOuterSVG(nsFrameConstructorState& aState,
                                          FrameConstructionItem&   aItem,
                                          nsIFrame*                aParentFrame,
                                          const nsStyleDisplay*    aDisplay,
                                          nsFrameItems&            aFrameItems)
 {
   return ConstructFrameWithAnonymousChild(
       aState, aItem, aParentFrame, aDisplay, aFrameItems,
       NS_NewSVGOuterSVGFrame, NS_NewSVGOuterSVGAnonChildFrame,
       nsCSSAnonBoxes::mozSVGOuterSVGAnonChild, true);
 }
 nsIFrame*
 nsCSSFrameConstructor::ConstructMarker(nsFrameConstructorState& aState,
                                        FrameConstructionItem&   aItem,
                                        nsIFrame*                aParentFrame,
                                        const nsStyleDisplay*    aDisplay,
                                        nsFrameItems&            aFrameItems)
 {
   return ConstructFrameWithAnonymousChild(
       aState, aItem, aParentFrame, aDisplay, aFrameItems,
       NS_NewSVGMarkerFrame, NS_NewSVGMarkerAnonChildFrame,
       nsCSSAnonBoxes::mozSVGMarkerAnonChild, false);
 }
 // Only outer <svg> elements can be floated or positioned.  All other SVG
 // should be in-flow.
 #define SIMPLE_SVG_FCDATA(_func)                                        \
   FCDATA_DECL(FCDATA_DISALLOW_OUT_OF_FLOW |                             \
               FCDATA_SKIP_ABSPOS_PUSH |                                 \
               FCDATA_DISALLOW_GENERATED_CONTENT,  _func)
 #define SIMPLE_SVG_CREATE(_tag, _func)            \
   { &nsGkAtoms::_tag, SIMPLE_SVG_FCDATA(_func) }
 static bool
 IsFilterPrimitiveChildTag(const nsIAtom* aTag)
 {
   return aTag == nsGkAtoms::feDistantLight ||
          aTag == nsGkAtoms::fePointLight ||
          aTag == nsGkAtoms::feSpotLight ||
          aTag == nsGkAtoms::feFuncR ||
          aTag == nsGkAtoms::feFuncG ||
          aTag == nsGkAtoms::feFuncB ||
          aTag == nsGkAtoms::feFuncA ||
          aTag == nsGkAtoms::feMergeNode;
 }
 /* static */
 const nsCSSFrameConstructor::FrameConstructionData*
 nsCSSFrameConstructor::FindSVGData(Element* aElement,
                                    nsIAtom* aTag,
                                    int32_t aNameSpaceID,
                                    nsIFrame* aParentFrame,
                                    bool aIsWithinSVGText,
                                    bool aAllowsTextPathChild,
                                    nsStyleContext* aStyleContext)
 {
   if (aNameSpaceID != kNameSpaceID_SVG) {
     return nullptr;
   }
   static const FrameConstructionData sSuppressData = SUPPRESS_FCDATA();
   static const FrameConstructionData sContainerData =
     SIMPLE_SVG_FCDATA(NS_NewSVGContainerFrame);
   bool parentIsSVG = aIsWithinSVGText;
   nsIContent* parentContent =
     aParentFrame ? aParentFrame->GetContent() : nullptr;
   // XXXbz should this really be based on the XBL-resolved tag of the parent
   // frame's content?  Should it not be based on the type of the parent frame
   // (e.g. whether it's an SVG frame)?
   if (parentContent) {
     int32_t parentNSID;
     nsIAtom* parentTag =
       parentContent->OwnerDoc()->BindingManager()->
         ResolveTag(parentContent, &parentNSID);
     // It's not clear whether the SVG spec intends to allow any SVG
     // content within svg:foreignObject at all (SVG 1.1, section
     // 23.2), but if it does, it better be svg:svg.  So given that
     // we're allowing it, treat it as a non-SVG parent.
     parentIsSVG = parentNSID == kNameSpaceID_SVG &&
                   parentTag != nsGkAtoms::foreignObject;
   }
   if ((aTag != nsGkAtoms::svg && !parentIsSVG) ||
       (aTag == nsGkAtoms::desc || aTag == nsGkAtoms::title)) {
     // Sections 5.1 and G.4 of SVG 1.1 say that SVG elements other than
     // svg:svg not contained within svg:svg are incorrect, although they
     // don't seem to specify error handling.  Ignore them, since many of
     // our frame classes can't deal.  It *may* be that the document
     // should at that point be considered in error according to F.2, but
     // it's hard to tell.
     //
     // Style mutation can't change this situation, so don't bother
     // adding to the undisplayed content map.
     //
     // We don't currently handle any UI for desc/title
     return &sSuppressData;
   }
   // We don't need frames for animation elements
   if (aElement->IsNodeOfType(nsINode::eANIMATION)) {
     return &sSuppressData;
   }
   if (aTag == nsGkAtoms::svg && !parentIsSVG) {
     // We need outer <svg> elements to have an nsSVGOuterSVGFrame regardless
     // of whether they fail conditional processing attributes, since various
     // SVG frames assume that one exists.  We handle the non-rendering
     // of failing outer <svg> element contents like <switch> statements,
     // and do the PassesConditionalProcessingTests call in
     // nsSVGOuterSVGFrame::Init.
     static const FrameConstructionData sOuterSVGData =
       FULL_CTOR_FCDATA(0, &nsCSSFrameConstructor::ConstructOuterSVG);
     return &sOuterSVGData;
   }
   if (aTag == nsGkAtoms::marker) {
     static const FrameConstructionData sMarkerSVGData =
       FULL_CTOR_FCDATA(0, &nsCSSFrameConstructor::ConstructMarker);
     return &sMarkerSVGData;
   }
   nsCOMPtr<SVGTests> tests(do_QueryInterface(aElement));
   if (tests && !tests->PassesConditionalProcessingTests()) {
     // Elements with failing conditional processing attributes never get
     // rendered.  Note that this is not where we select which frame in a
     // <switch> to render!  That happens in nsSVGSwitchFrame::PaintSVG.
     return &sContainerData;
   }
   // Prevent bad frame types being children of filters or parents of filter
   // primitives.  If aParentFrame is null, we know that the frame that will
   // be created will be an nsInlineFrame, so it can never be a filter.
   bool parentIsFilter = aParentFrame &&
     aParentFrame->GetType() == nsGkAtoms::svgFilterFrame;
   bool filterPrimitive = aElement->IsNodeOfType(nsINode::eFILTER);
   if ((parentIsFilter && !filterPrimitive) ||
       (!parentIsFilter && filterPrimitive)) {
     return &sSuppressData;
   }
   // Prevent bad frame types being children of filter primitives or parents of
   // filter primitive children.  If aParentFrame is null, we know that the frame
   // that will be created will be an nsInlineFrame, so it can never be a filter
   // primitive.
   bool parentIsFEContainerFrame = aParentFrame &&
     aParentFrame->GetType() == nsGkAtoms::svgFEContainerFrame;
   if ((parentIsFEContainerFrame && !IsFilterPrimitiveChildTag(aTag)) ||
       (!parentIsFEContainerFrame && IsFilterPrimitiveChildTag(aTag))) {
     return &sSuppressData;
   }
   // Special cases for text/tspan/textPath, because the kind of frame
   // they get depends on the parent frame.  We ignore 'a' elements when
   // determining the parent, however.
   if (aIsWithinSVGText) {
     // If aIsWithinSVGText is true, then we know that the "SVG text uses
     // CSS frames" pref was true when this SVG fragment was first constructed.
     // We don't use ConstructInline because we want different behavior
     // for generated content.
     static const FrameConstructionData sTSpanData =
       FCDATA_DECL(FCDATA_DISALLOW_OUT_OF_FLOW |
                   FCDATA_SKIP_ABSPOS_PUSH |
                   FCDATA_DISALLOW_GENERATED_CONTENT |
                   FCDATA_IS_LINE_PARTICIPANT |
                   FCDATA_IS_INLINE |
                   FCDATA_USE_CHILD_ITEMS,
                   NS_NewInlineFrame);
     if (aTag == nsGkAtoms::textPath) {
       if (aAllowsTextPathChild) {
         return &sTSpanData;
       }
     } else if (aTag == nsGkAtoms::tspan ||
                aTag == nsGkAtoms::altGlyph ||
                aTag == nsGkAtoms::a) {
       return &sTSpanData;
     }
     return &sSuppressData;
   } else if (aTag == nsGkAtoms::text) {
     static const FrameConstructionData sTextData =
       FCDATA_WITH_WRAPPING_BLOCK(FCDATA_DISALLOW_OUT_OF_FLOW |
                                  FCDATA_ALLOW_BLOCK_STYLES,
                                  NS_NewSVGTextFrame,
                                  nsCSSAnonBoxes::mozSVGText);
     return &sTextData;
   } else if (aTag == nsGkAtoms::tspan ||
              aTag == nsGkAtoms::altGlyph ||
              aTag == nsGkAtoms::textPath) {
     return &sSuppressData;
   }
   static const FrameConstructionDataByTag sSVGData[] = {
     SIMPLE_SVG_CREATE(svg, NS_NewSVGInnerSVGFrame),
     SIMPLE_SVG_CREATE(g, NS_NewSVGGFrame),
     SIMPLE_SVG_CREATE(svgSwitch, NS_NewSVGSwitchFrame),
     SIMPLE_SVG_CREATE(polygon, NS_NewSVGPathGeometryFrame),
     SIMPLE_SVG_CREATE(polyline, NS_NewSVGPathGeometryFrame),
     SIMPLE_SVG_CREATE(circle, NS_NewSVGPathGeometryFrame),
     SIMPLE_SVG_CREATE(ellipse, NS_NewSVGPathGeometryFrame),
     SIMPLE_SVG_CREATE(line, NS_NewSVGPathGeometryFrame),
     SIMPLE_SVG_CREATE(rect, NS_NewSVGPathGeometryFrame),
     SIMPLE_SVG_CREATE(path, NS_NewSVGPathGeometryFrame),
     SIMPLE_SVG_CREATE(defs, NS_NewSVGContainerFrame),
     SIMPLE_SVG_CREATE(generic_, NS_NewSVGGenericContainerFrame),
     { &nsGkAtoms::foreignObject,
       FCDATA_WITH_WRAPPING_BLOCK(FCDATA_DISALLOW_OUT_OF_FLOW,
                                  NS_NewSVGForeignObjectFrame,
                                  nsCSSAnonBoxes::mozSVGForeignContent) },
     SIMPLE_SVG_CREATE(a, NS_NewSVGAFrame),
     SIMPLE_SVG_CREATE(linearGradient, NS_NewSVGLinearGradientFrame),
     SIMPLE_SVG_CREATE(radialGradient, NS_NewSVGRadialGradientFrame),
     SIMPLE_SVG_CREATE(stop, NS_NewSVGStopFrame),
     SIMPLE_SVG_CREATE(use, NS_NewSVGUseFrame),
     SIMPLE_SVG_CREATE(view, NS_NewSVGViewFrame),
     SIMPLE_SVG_CREATE(image, NS_NewSVGImageFrame),
     SIMPLE_SVG_CREATE(clipPath, NS_NewSVGClipPathFrame),
     SIMPLE_SVG_CREATE(filter, NS_NewSVGFilterFrame),
     SIMPLE_SVG_CREATE(pattern, NS_NewSVGPatternFrame),
     SIMPLE_SVG_CREATE(mask, NS_NewSVGMaskFrame),
     SIMPLE_SVG_CREATE(feDistantLight, NS_NewSVGFEUnstyledLeafFrame),
     SIMPLE_SVG_CREATE(fePointLight, NS_NewSVGFEUnstyledLeafFrame),
     SIMPLE_SVG_CREATE(feSpotLight, NS_NewSVGFEUnstyledLeafFrame),
     SIMPLE_SVG_CREATE(feBlend, NS_NewSVGFELeafFrame),
     SIMPLE_SVG_CREATE(feColorMatrix, NS_NewSVGFELeafFrame),
     SIMPLE_SVG_CREATE(feFuncR, NS_NewSVGFEUnstyledLeafFrame),
     SIMPLE_SVG_CREATE(feFuncG, NS_NewSVGFEUnstyledLeafFrame),
     SIMPLE_SVG_CREATE(feFuncB, NS_NewSVGFEUnstyledLeafFrame),
     SIMPLE_SVG_CREATE(feFuncA, NS_NewSVGFEUnstyledLeafFrame),
     SIMPLE_SVG_CREATE(feComposite, NS_NewSVGFELeafFrame),
     SIMPLE_SVG_CREATE(feComponentTransfer, NS_NewSVGFEContainerFrame),
     SIMPLE_SVG_CREATE(feConvolveMatrix, NS_NewSVGFELeafFrame),
     SIMPLE_SVG_CREATE(feDiffuseLighting, NS_NewSVGFEContainerFrame),
     SIMPLE_SVG_CREATE(feDisplacementMap, NS_NewSVGFELeafFrame),
     SIMPLE_SVG_CREATE(feDropShadow, NS_NewSVGFELeafFrame),
     SIMPLE_SVG_CREATE(feFlood, NS_NewSVGFELeafFrame),
     SIMPLE_SVG_CREATE(feGaussianBlur, NS_NewSVGFELeafFrame),
     SIMPLE_SVG_CREATE(feImage, NS_NewSVGFEImageFrame),
     SIMPLE_SVG_CREATE(feMerge, NS_NewSVGFEContainerFrame),
     SIMPLE_SVG_CREATE(feMergeNode, NS_NewSVGFEUnstyledLeafFrame),
     SIMPLE_SVG_CREATE(feMorphology, NS_NewSVGFELeafFrame),
     SIMPLE_SVG_CREATE(feOffset, NS_NewSVGFELeafFrame),
     SIMPLE_SVG_CREATE(feSpecularLighting, NS_NewSVGFEContainerFrame),
     SIMPLE_SVG_CREATE(feTile, NS_NewSVGFELeafFrame),
     SIMPLE_SVG_CREATE(feTurbulence, NS_NewSVGFELeafFrame)
   };
   const FrameConstructionData* data =
     FindDataByTag(aTag, aElement, aStyleContext, sSVGData,
                   ArrayLength(sSVGData));
   if (!data) {
     data = &sContainerData;
   }
   return data;
 }
 void
 nsCSSFrameConstructor::AddPageBreakItem(nsIContent* aContent,
                                         nsStyleContext* aMainStyleContext,
                                         FrameConstructionItemList& aItems)
 {
   // Use the same parent style context that |aMainStyleContext| has, since
   // that's easier to re-resolve and it doesn't matter in practice.
   // (Getting different parents can result in framechange hints, e.g.,
   // for user-modify.)
   nsRefPtr<nsStyleContext> pseudoStyle =
     mPresShell->StyleSet()->
       ResolveAnonymousBoxStyle(nsCSSAnonBoxes::pageBreak,
                                aMainStyleContext->GetParent());
   NS_ASSERTION(pseudoStyle->StyleDisplay()->mDisplay ==
                  NS_STYLE_DISPLAY_BLOCK, "Unexpected display");
   static const FrameConstructionData sPageBreakData =
     FCDATA_DECL(FCDATA_SKIP_FRAMESET, NS_NewPageBreakFrame);
   // Lie about the tag and namespace so we don't trigger anything
   // interesting during frame construction.
   aItems.AppendItem(&sPageBreakData, aContent, nsCSSAnonBoxes::pageBreak,
                     kNameSpaceID_None, nullptr, pseudoStyle.forget(),
                     true, nullptr);
 }
 void
 nsCSSFrameConstructor::AddFrameConstructionItems(nsFrameConstructorState& aState,
                                                  nsIContent* aContent,
                                                  bool aSuppressWhiteSpaceOptimizations,
                                                  nsIFrame* aParentFrame,
                                                  FrameConstructionItemList& aItems)
 {
   aContent->UnsetFlags(NODE_DESCENDANTS_NEED_FRAMES | NODE_NEEDS_FRAME);
   if (aContent->IsElement()) {
     // We can't just remove our pending restyle flags, since we may
     // have restyle-later-siblings set on us.  But we _can_ remove the
     // "is possible restyle root" flags, and need to.  Otherwise we can
     // end up with stale such flags (e.g. if we used to have a
     // display:none parent when our last restyle was posted and
     // processed and now no longer do).
     aContent->UnsetFlags(ELEMENT_ALL_RESTYLE_FLAGS &
                          ~ELEMENT_PENDING_RESTYLE_FLAGS);
   }
   // XXX the GetContent() != aContent check is needed due to bug 135040.
   // Remove it once that's fixed.
   if (aContent->GetPrimaryFrame() &&
       aContent->GetPrimaryFrame()->GetContent() == aContent &&
       !aState.mCreatingExtraFrames) {
     NS_ERROR("asked to create frame construction item for a node that already "
              "has a frame");
     return;
   }
   // don't create a whitespace frame if aParent doesn't want it
   if (!NeedFrameFor(aState, aParentFrame, aContent)) {
     return;
   }
   // never create frames for comments or PIs
   if (aContent->IsNodeOfType(nsINode::eCOMMENT) ||
       aContent->IsNodeOfType(nsINode::ePROCESSING_INSTRUCTION))
     return;
   nsRefPtr<nsStyleContext> styleContext;
   styleContext = ResolveStyleContext(aParentFrame, aContent, &aState);
   uint32_t flags = ITEM_ALLOW_XBL_BASE | ITEM_ALLOW_PAGE_BREAK;
   if (aParentFrame->IsSVGText()) {
     flags |= ITEM_IS_WITHIN_SVG_TEXT;
   }
   if (aParentFrame->GetType() == nsGkAtoms::blockFrame &&
       aParentFrame->GetParent() &&
       aParentFrame->GetParent()->GetType() == nsGkAtoms::svgTextFrame) {
     flags |= ITEM_ALLOWS_TEXT_PATH_CHILD;
   }
   AddFrameConstructionItemsInternal(aState, aContent, aParentFrame,
                                     aContent->Tag(), aContent->GetNameSpaceID(),
                                     aSuppressWhiteSpaceOptimizations,
                                     styleContext,
                                     flags, nullptr,
                                     aItems);
 }
 /* static */ void
 nsCSSFrameConstructor::SetAsUndisplayedContent(FrameConstructionItemList& aList,
                                                nsIContent* aContent,
                                                nsStyleContext* aStyleContext,
                                                bool aIsGeneratedContent)
 {
   if (aStyleContext->GetPseudo()) {
     if (aIsGeneratedContent) {
       aContent->UnbindFromTree();
     }
     return;
   }
   NS_ASSERTION(!aIsGeneratedContent, "Should have had pseudo type");
   aList.AppendUndisplayedItem(aContent, aStyleContext);
 }
 void
 nsCSSFrameConstructor::AddFrameConstructionItemsInternal(nsFrameConstructorState& aState,
                                                          nsIContent* aContent,
                                                          nsIFrame* aParentFrame,
                                                          nsIAtom* aTag,
                                                          int32_t aNameSpaceID,
                                                          bool aSuppressWhiteSpaceOptimizations,
                                                          nsStyleContext* aStyleContext,
                                                          uint32_t aFlags,
                                                          nsTArray<nsIAnonymousContentCreator::ContentInfo>* aAnonChildren,
                                                          FrameConstructionItemList& aItems)
 {
   NS_PRECONDITION(aContent->IsNodeOfType(nsINode::eTEXT) ||
                   aContent->IsElement(),
                   "Shouldn't get anything else here!");
   // The following code allows the user to specify the base tag
   // of an element using XBL.  XUL and HTML objects (like boxes, menus, etc.)
   // can then be extended arbitrarily.
   const nsStyleDisplay* display = aStyleContext->StyleDisplay();
   nsRefPtr<nsStyleContext> styleContext(aStyleContext);
   PendingBinding* pendingBinding = nullptr;
   if ((aFlags & ITEM_ALLOW_XBL_BASE) && display->mBinding)
   {
     // Ensure that our XBL bindings are installed.
     nsXBLService* xblService = nsXBLService::GetInstance();
     if (!xblService)
       return;
     bool resolveStyle;
     nsAutoPtr<PendingBinding> newPendingBinding(new PendingBinding());
     nsresult rv = xblService->LoadBindings(aContent, display->mBinding->GetURI(),
                                            display->mBinding->mOriginPrincipal,
                                            getter_AddRefs(newPendingBinding->mBinding),
                                            &resolveStyle);
     if (NS_FAILED(rv) && rv != NS_ERROR_XBL_BLOCKED)
       return;
     if (newPendingBinding->mBinding) {
       pendingBinding = newPendingBinding;
       // aState takes over owning newPendingBinding
       aState.AddPendingBinding(newPendingBinding.forget());
     }
     if (resolveStyle) {
       styleContext =
         ResolveStyleContext(styleContext->GetParent(), aContent, &aState);
       display = styleContext->StyleDisplay();
       aStyleContext = styleContext;
     }
     aTag = mDocument->BindingManager()->ResolveTag(aContent, &aNameSpaceID);
   }
   bool isGeneratedContent = ((aFlags & ITEM_IS_GENERATED_CONTENT) != 0);
   // Pre-check for display "none" - if we find that, don't create
   // any frame at all
   if (NS_STYLE_DISPLAY_NONE == display->mDisplay) {
     SetAsUndisplayedContent(aItems, aContent, styleContext, isGeneratedContent);
     return;
   }
   bool isText = !aContent->IsElement();
   // never create frames for non-option/optgroup kids of <select> and
   // non-option kids of <optgroup> inside a <select>.
   // XXXbz it's not clear how this should best work with XBL.
   nsIContent *parent = aContent->GetParent();
   if (parent) {
     // Check tag first, since that check will usually fail
     nsIAtom* parentTag = parent->Tag();
     if ((parentTag == nsGkAtoms::select || parentTag == nsGkAtoms::optgroup) &&
         parent->IsHTML() &&
         // <option> is ok no matter what
         !aContent->IsHTML(nsGkAtoms::option) &&
         // <optgroup> is OK in <select> but not in <optgroup>
         (!aContent->IsHTML(nsGkAtoms::optgroup) ||
          parentTag != nsGkAtoms::select) &&
         // Allow native anonymous content no matter what
         !aContent->IsRootOfNativeAnonymousSubtree()) {
       // No frame for aContent
       if (!isText) {
         SetAsUndisplayedContent(aItems, aContent, styleContext,
                                 isGeneratedContent);
       }
       return;
     }
   }
   bool isPopup = false;
   // Try to find frame construction data for this content
   const FrameConstructionData* data;
   if (isText) {
     data = FindTextData(aParentFrame);
     if (!data) {
       // Nothing to do here; suppressed text inside SVG
       return;
     }
   } else {
     Element* element = aContent->AsElement();
     // Don't create frames for non-SVG element children of SVG elements.
     if (aNameSpaceID != kNameSpaceID_SVG &&
         ((aParentFrame &&
           IsFrameForSVG(aParentFrame) &&
           !aParentFrame->IsFrameOfType(nsIFrame::eSVGForeignObject)) ||
          (aFlags & ITEM_IS_WITHIN_SVG_TEXT))) {
       SetAsUndisplayedContent(aItems, element, styleContext,
                               isGeneratedContent);
       return;
     }
     data = FindHTMLData(element, aTag, aNameSpaceID, aParentFrame,
                         styleContext);
     if (!data) {
       data = FindXULTagData(element, aTag, aNameSpaceID, styleContext);
     }
     if (!data) {
       data = FindMathMLData(element, aTag, aNameSpaceID, styleContext);
     }
     if (!data) {
       data = FindSVGData(element, aTag, aNameSpaceID, aParentFrame,
                          aFlags & ITEM_IS_WITHIN_SVG_TEXT,
                          aFlags & ITEM_ALLOWS_TEXT_PATH_CHILD,
                          styleContext);
     }
     // Now check for XUL display types
     if (!data) {
       data = FindXULDisplayData(display, element, styleContext);
     }
     // And general display types
     if (!data) {
       data = FindDisplayData(display, element, aParentFrame, styleContext);
     }
     NS_ASSERTION(data, "Should have frame construction data now");
     if (data->mBits & FCDATA_SUPPRESS_FRAME) {
       SetAsUndisplayedContent(aItems, element, styleContext, isGeneratedContent);
       return;
     }
 #ifdef MOZ_XUL
     if ((data->mBits & FCDATA_IS_POPUP) &&
         (!aParentFrame || // Parent is inline
          aParentFrame->GetType() != nsGkAtoms::menuFrame)) {
       if (!aState.mPopupItems.containingBlock &&
           !aState.mHavePendingPopupgroup) {
         SetAsUndisplayedContent(aItems, element, styleContext,
                                 isGeneratedContent);
         return;
       }
       isPopup = true;
     }
 #endif /* MOZ_XUL */
   }
   uint32_t bits = data->mBits;
   // Inside colgroups, suppress everything except columns.
   if (aParentFrame &&
       aParentFrame->GetType() == nsGkAtoms::tableColGroupFrame &&
       (!(bits & FCDATA_IS_TABLE_PART) ||
        display->mDisplay != NS_STYLE_DISPLAY_TABLE_COLUMN)) {
     SetAsUndisplayedContent(aItems, aContent, styleContext, isGeneratedContent);
     return;
   }
   bool canHavePageBreak =
     (aFlags & ITEM_ALLOW_PAGE_BREAK) &&
     aState.mPresContext->IsPaginated() &&
     !display->IsAbsolutelyPositionedStyle() &&
     !(bits & FCDATA_IS_TABLE_PART) &&
     !(bits & FCDATA_IS_SVG_TEXT);
   if (canHavePageBreak && display->mBreakBefore) {
     AddPageBreakItem(aContent, aStyleContext, aItems);
   }
   FrameConstructionItem* item =
     aItems.AppendItem(data, aContent, aTag, aNameSpaceID,
                       pendingBinding, styleContext.forget(),
                       aSuppressWhiteSpaceOptimizations, aAnonChildren);
   if (!item) {
     if (isGeneratedContent) {
       aContent->UnbindFromTree();
     }
     return;
   }
   item->mIsText = isText;
   item->mIsGeneratedContent = isGeneratedContent;
   item->mIsAnonymousContentCreatorContent =
     aFlags & ITEM_IS_ANONYMOUSCONTENTCREATOR_CONTENT;
   if (isGeneratedContent) {
     NS_ADDREF(item->mContent);
   }
   item->mIsRootPopupgroup =
     aNameSpaceID == kNameSpaceID_XUL && aTag == nsGkAtoms::popupgroup &&
     aContent->IsRootOfNativeAnonymousSubtree();
   if (item->mIsRootPopupgroup) {
     aState.mHavePendingPopupgroup = true;
   }
   item->mIsPopup = isPopup;
   item->mIsForSVGAElement = aNameSpaceID == kNameSpaceID_SVG &&
                             aTag == nsGkAtoms::a;
   if (canHavePageBreak && display->mBreakAfter) {
     AddPageBreakItem(aContent, aStyleContext, aItems);
   }
   if (bits & FCDATA_IS_INLINE) {
     // To correctly set item->mIsAllInline we need to build up our child items
     // right now.
     BuildInlineChildItems(aState, *item,
                           aFlags & ITEM_IS_WITHIN_SVG_TEXT,
                           aFlags & ITEM_ALLOWS_TEXT_PATH_CHILD);
     item->mHasInlineEnds = true;
     item->mIsBlock = false;
   } else {
     // Compute a boolean isInline which is guaranteed to be false for blocks
     // (but may also be false for some inlines).
     bool isInline =
       // Table-internal things are inline-outside if and only if they're kids of
       // inlines, since they'll trigger construction of inline-table
       // pseudos.
       ((bits & FCDATA_IS_TABLE_PART) &&
        (!aParentFrame || // No aParentFrame means inline
         aParentFrame->StyleDisplay()->mDisplay == NS_STYLE_DISPLAY_INLINE)) ||
       // Things that are inline-outside but aren't inline frames are inline
       display->IsInlineOutsideStyle() ||
       // Popups that are certainly out of flow.
       isPopup;
     // Set mIsAllInline conservatively.  It just might be that even an inline
     // that has mIsAllInline false doesn't need an {ib} split.  So this is just
     // an optimization to keep from doing too much work in cases when we can
     // show that mIsAllInline is true..
     item->mIsAllInline = item->mHasInlineEnds = isInline ||
       // Figure out whether we're guaranteed this item will be out of flow.
       // This is not a precise test, since one of our ancestor inlines might add
       // an absolute containing block (if it's relatively positioned) when there
       // wasn't such a containing block before.  But it's conservative in the
       // sense that anything that will really end up as an in-flow non-inline
       // will test false here.  In other words, if this test is true we're
       // guaranteed to be inline; if it's false we don't know what we'll end up
       // as.
       //
       // If we make this test precise, we can remove some of the code dealing
       // with the imprecision in ConstructInline and adjust the comments on
       // mIsAllInline and mIsBlock in the header.  And probably remove mIsBlock
       // altogether, since then it will always be equal to !mHasInlineEnds.
       (!(bits & FCDATA_DISALLOW_OUT_OF_FLOW) &&
        aState.GetGeometricParent(display, nullptr));
     // Set mIsBlock conservatively.  It's OK to set it false for some real
     // blocks, but not OK to set it true for things that aren't blocks.  Since
     // isOutOfFlow might be false even in cases when the frame will end up
     // out-of-flow, we can't use it here.  But we _can_ say that the frame will
     // for sure end up in-flow if it's not floated or absolutely positioned.
     item->mIsBlock = !isInline &&
                      !display->IsAbsolutelyPositionedStyle() &&
                      !display->IsFloatingStyle() &&
                      !(bits & FCDATA_IS_SVG_TEXT);
   }
   if (item->mIsAllInline) {
     aItems.InlineItemAdded();
   } else if (item->mIsBlock) {
     aItems.BlockItemAdded();
   }
   // Our item should be treated as a line participant if we have the relevant
   // bit and are going to be in-flow.  Note that this really only matters if
   // our ancestor is a box or some such, so the fact that we might have an
   // inline ancestor that might become a containing block is not relevant here.
   if ((bits & FCDATA_IS_LINE_PARTICIPANT) &&
       ((bits & FCDATA_DISALLOW_OUT_OF_FLOW) ||
        !aState.GetGeometricParent(display, nullptr))) {
     item->mIsLineParticipant = true;
     aItems.LineParticipantItemAdded();
   }
 }
 static void
 DestroyContent(void* aPropertyValue)
 {
   nsIContent* content = static_cast<nsIContent*>(aPropertyValue);
   content->UnbindFromTree();
   NS_RELEASE(content);
 }
 NS_DECLARE_FRAME_PROPERTY(BeforeProperty, DestroyContent)
 NS_DECLARE_FRAME_PROPERTY(AfterProperty, DestroyContent)
 static const FramePropertyDescriptor*
 GenConPseudoToProperty(nsIAtom* aPseudo)
 {
   NS_ASSERTION(aPseudo == nsCSSPseudoElements::before ||
                aPseudo == nsCSSPseudoElements::after,
                "Bad gen-con pseudo");
   return aPseudo == nsCSSPseudoElements::before ? BeforeProperty()
       : AfterProperty();
 }
 /**
  * Return true if the frame construction item pointed to by aIter will
  * create a frame adjacent to a line boundary in the frame tree, and that
  * line boundary is induced by a content node adjacent to the frame's
  * content node in the content tree. The latter condition is necessary so
  * that ContentAppended/ContentInserted/ContentRemoved can easily find any
  * text nodes that were suppressed here.
  */
 bool
 nsCSSFrameConstructor::AtLineBoundary(FCItemIterator& aIter)
 {
   if (aIter.item().mSuppressWhiteSpaceOptimizations) {
     return false;
   }
   if (aIter.AtStart()) {
     if (aIter.List()->HasLineBoundaryAtStart() &&
         !aIter.item().mContent->GetPreviousSibling())
       return true;
   } else {
     FCItemIterator prev = aIter;
     prev.Prev();
     if (prev.item().IsLineBoundary() &&
         !prev.item().mSuppressWhiteSpaceOptimizations &&
         aIter.item().mContent->GetPreviousSibling() == prev.item().mContent)
       return true;
   }
   FCItemIterator next = aIter;
   next.Next();
   if (next.IsDone()) {
     if (aIter.List()->HasLineBoundaryAtEnd() &&
         !aIter.item().mContent->GetNextSibling())
       return true;
   } else {
     if (next.item().IsLineBoundary() &&
         !next.item().mSuppressWhiteSpaceOptimizations &&
         aIter.item().mContent->GetNextSibling() == next.item().mContent)
       return true;
   }
   return false;
 }
 void
 nsCSSFrameConstructor::ConstructFramesFromItem(nsFrameConstructorState& aState,
                                                FCItemIterator& aIter,
                                                nsIFrame* aParentFrame,
                                                nsFrameItems& aFrameItems)
 {
   nsIFrame* adjParentFrame = aParentFrame;
   FrameConstructionItem& item = aIter.item();
   nsStyleContext* styleContext = item.mStyleContext;
   AdjustParentFrame(adjParentFrame, item.mFCData, styleContext);
   if (item.mIsText) {
     // If this is collapsible whitespace next to a line boundary,
     // don't create a frame. item.IsWhitespace() also sets the
     // NS_CREATE_FRAME_IF_NON_WHITESPACE flag in the text node. (If we
     // end up creating a frame, nsTextFrame::Init will clear the flag.)
     // We don't do this for generated content, because some generated
     // text content is empty text nodes that are about to be initialized.
     // (We check mAdditionalStateBits because only the generated content
     // container's frame construction item is marked with
     // mIsGeneratedContent, and we might not have an aParentFrame.)
     // We don't do it for content that may have XBL anonymous siblings,
     // because they make it difficult to correctly create the frame
     // due to dynamic changes.
     // We don't do it for SVG text, since we might need to position and
     // measure the white space glyphs due to x/y/dx/dy attributes.
     if (AtLineBoundary(aIter) &&
         !styleContext->StyleText()->WhiteSpaceOrNewlineIsSignificant() &&
         aIter.List()->ParentHasNoXBLChildren() &&
         !(aState.mAdditionalStateBits & NS_FRAME_GENERATED_CONTENT) &&
         (item.mFCData->mBits & FCDATA_IS_LINE_PARTICIPANT) &&
         !(item.mFCData->mBits & FCDATA_IS_SVG_TEXT) &&
         !mAlwaysCreateFramesForIgnorableWhitespace &&
         item.IsWhitespace(aState))
       return;
     ConstructTextFrame(item.mFCData, aState, item.mContent,
                        adjParentFrame, styleContext,
                        aFrameItems);
     return;
   }
   // Start background loads during frame construction so that we're
   // guaranteed that they will be started before onload fires.
   styleContext->StartBackgroundImageLoads();
   nsFrameState savedStateBits = aState.mAdditionalStateBits;
   if (item.mIsGeneratedContent) {
     // Ensure that frames created here are all tagged with
     // NS_FRAME_GENERATED_CONTENT.
     aState.mAdditionalStateBits |= NS_FRAME_GENERATED_CONTENT;
     // Note that we're not necessarily setting this property on the primary
     // frame for the content for which this is generated content.  We might be
     // setting it on a table pseudo-frame inserted under that instead.  That's
     // OK, though; we just need to do the property set so that the content will
     // get cleaned up when the frame is destroyed.
     aParentFrame->Properties().Set(GenConPseudoToProperty(styleContext->GetPseudo()),
                                    item.mContent);
     // Now that we've passed ownership of item.mContent to the frame, unset
     // our generated content flag so we don't release or unbind it ourselves.
     item.mIsGeneratedContent = false;
   }
   // XXXbz maybe just inline ConstructFrameFromItemInternal here or something?
   ConstructFrameFromItemInternal(item, aState, adjParentFrame, aFrameItems);
   aState.mAdditionalStateBits = savedStateBits;
 }
 inline bool
 IsRootBoxFrame(nsIFrame *aFrame)
 {
   return (aFrame->GetType() == nsGkAtoms::rootFrame);
 }
 nsresult
 nsCSSFrameConstructor::ReconstructDocElementHierarchy()
 {
   Element* rootElement = mDocument->GetRootElement();
   if (!rootElement) {
     /* nothing to do */
     return NS_OK;
   }
   return RecreateFramesForContent(rootElement, false);
 }
 nsIFrame*
 nsCSSFrameConstructor::GetFrameFor(nsIContent* aContent)
 {
   // Get the primary frame associated with the content
   nsIFrame* frame = aContent->GetPrimaryFrame();
   if (!frame)
     return nullptr;
   // If the content of the frame is not the desired content then this is not
   // really a frame for the desired content.
   // XXX This check is needed due to bug 135040. Remove it once that's fixed.
   if (frame->GetContent() != aContent) {
     return nullptr;
   }
   nsIFrame* insertionFrame = frame->GetContentInsertionFrame();
   NS_ASSERTION(insertionFrame == frame || !frame->IsLeaf(),
     "The insertion frame is the primary frame or the primary frame isn't a leaf");
   return insertionFrame;
 }
 nsIFrame*
 nsCSSFrameConstructor::GetAbsoluteContainingBlock(nsIFrame* aFrame,
                                                   ContainingBlockType aType)
 {
   NS_PRECONDITION(nullptr != mRootElementFrame, "no root element frame");
   // Starting with aFrame, look for a frame that is absolutely positioned or
   // relatively positioned (and transformed, if aType is FIXED)
   for (nsIFrame* frame = aFrame; frame; frame = frame->GetParent()) {
     if (frame->IsFrameOfType(nsIFrame::eMathML)) {
       // If it's mathml, bail out -- no absolute positioning out from inside
       // mathml frames.  Note that we don't make this part of the loop
       // condition because of the stuff at the end of this method...
       return nullptr;
     }
     // If the frame is positioned, we will probably return it as the containing
     // block (see the exceptions below).  Otherwise, we'll start looking at the
     // parent frame, unless we're dealing with a scrollframe.
     // Scrollframes are special since they're not positioned, but their
     // scrolledframe might be.  So, we need to check this special case to return
     // the correct containing block (the scrolledframe) in that case.
     // If we're looking for a fixed-pos containing block and the frame is
     // not transformed, skip it.
     if (!frame->IsPositioned() ||
         (aType == FIXED_POS &&
          !frame->StyleDisplay()->HasTransform(frame) &&
          !frame->StyleDisplay()->HasPerspectiveStyle())) {
       continue;
     }
     nsIFrame* absPosCBCandidate = frame;
     nsIAtom* type = absPosCBCandidate->GetType();
     if (type == nsGkAtoms::fieldSetFrame) {
       absPosCBCandidate = static_cast<nsFieldSetFrame*>(absPosCBCandidate)->GetInner();
       if (!absPosCBCandidate) {
         continue;
       }
       type = absPosCBCandidate->GetType();
     }
     if (type == nsGkAtoms::scrollFrame) {
       nsIScrollableFrame* scrollFrame = do_QueryFrame(absPosCBCandidate);
       absPosCBCandidate = scrollFrame->GetScrolledFrame();
       if (!absPosCBCandidate) {
         continue;
       }
       type = absPosCBCandidate->GetType();
     }
     // Only first continuations can be containing blocks.
     absPosCBCandidate = absPosCBCandidate->FirstContinuation();
     // Is the frame really an absolute container?
     if (!absPosCBCandidate->IsAbsoluteContainer()) {
       continue;
     }
     // For tables, skip the inner frame and consider the outer table frame.
     if (type == nsGkAtoms::tableFrame) {
       continue;
     }
     // For outer table frames, we can just return absPosCBCandidate.
     return absPosCBCandidate;
   }
   // It is possible for the search for the containing block to fail, because
   // no absolute container can be found in the parent chain.  In those cases,
   // we fall back to the document element's containing block.
   if (aType == FIXED_POS) {
     return mFixedContainingBlock;
   }
   return mHasRootAbsPosContainingBlock ? mDocElementContainingBlock : nullptr;
 }
 nsIFrame*
 nsCSSFrameConstructor::GetFloatContainingBlock(nsIFrame* aFrame)
 {
   // Starting with aFrame, look for a frame that is a float containing block.
   // IF we hit a mathml frame, bail out; we don't allow floating out of mathml
   // frames, because they don't seem to be able to deal.
   // The logic here needs to match the logic in ProcessChildren()
   for (nsIFrame* containingBlock = aFrame;
        containingBlock &&
          !ShouldSuppressFloatingOfDescendants(containingBlock);
        containingBlock = containingBlock->GetParent()) {
     if (containingBlock->IsFloatContainingBlock()) {
       return containingBlock;
     }
   }
   // If we didn't find a containing block, then there just isn't
   // one.... return null
   return nullptr;
 }
 /**
  * This function will check whether aContainer has :after generated content.
  * If so, appending to it should actually insert.  The return value is the
  * parent to use for newly-appended content.  *aAfterFrame points to the :after
  * frame before which appended content should go, if there is one.
  */
 static nsIFrame*
 AdjustAppendParentForAfterContent(nsPresContext* aPresContext,
                                   nsIContent* aContainer,
                                   nsIFrame* aParentFrame,
                                   nsIFrame** aAfterFrame)
 {
   // See if the parent has an :after pseudo-element.  Check for the presence
   // of style first, since nsLayoutUtils::GetAfterFrame is sorta expensive.
   nsStyleContext* parentStyle = aParentFrame->StyleContext();
   if (nsLayoutUtils::HasPseudoStyle(aContainer, parentStyle,
                                     nsCSSPseudoElements::ePseudo_after,
                                     aPresContext)) {
     // Ensure that the :after frame is on the principal child list.
     aParentFrame->DrainSelfOverflowList();
     nsIFrame* afterFrame = nsLayoutUtils::GetAfterFrame(aParentFrame);
     if (afterFrame) {
       *aAfterFrame = afterFrame;
       return afterFrame->GetParent();
     }
   }
   *aAfterFrame = nullptr;
   if (IsFramePartOfIBSplit(aParentFrame)) {
     // We might be in a situation where the last part of the {ib} split was
     // empty.  Since we have no ::after pseudo-element, we do in fact want to be
     // appending to that last part, so advance to it if needed.  Note that here
     // aParentFrame is the result of a GetLastIBSplitSibling call, so must be
     // either the last or next to last ib-split sibling.
     nsIFrame* trailingInline = GetIBSplitSibling(aParentFrame);
     if (trailingInline) {
       aParentFrame = trailingInline;
     }
     // Always make sure to look at the last continuation of the frame
     // for the {ib} case, even if that continuation is empty.  We
     // don't do this for the non-ib-split-frame case, since in the
     // other cases appending to the last nonempty continuation is fine
     // and in fact not doing that can confuse code that doesn't know
     // to pull kids from continuations other than its next one.
     aParentFrame = aParentFrame->LastContinuation();
   }
   return aParentFrame;
 }
 /**
  * This function will get the previous sibling to use for an append operation.
  * it takes a parent frame (must not be null) and its :after frame (may be
  * null).
  */
 static nsIFrame*
 FindAppendPrevSibling(nsIFrame* aParentFrame, nsIFrame* aAfterFrame)
 {
   if (aAfterFrame) {
     NS_ASSERTION(aAfterFrame->GetParent() == aParentFrame, "Wrong parent");
     NS_ASSERTION(aAfterFrame->GetPrevSibling() ||
                  aParentFrame->GetFirstPrincipalChild() == aAfterFrame,
                  ":after frame must be on the principal child list here");
     return aAfterFrame->GetPrevSibling();
   }
   aParentFrame->DrainSelfOverflowList();
   return aParentFrame->GetLastChild(kPrincipalList);
 }
 /**
  * This function will get the next sibling for a frame insert operation given
  * the parent and previous sibling.  aPrevSibling may be null.
  */
 static nsIFrame*
 GetInsertNextSibling(nsIFrame* aParentFrame, nsIFrame* aPrevSibling)
 {
   if (aPrevSibling) {
     return aPrevSibling->GetNextSibling();
   }
   return aParentFrame->GetFirstPrincipalChild();
 }
 /**
  * This function is called by ContentAppended() and ContentInserted() when
  * appending flowed frames to a parent's principal child list. It handles the
  * case where the parent is the trailing inline of an {ib} split.
  */
 nsresult
 nsCSSFrameConstructor::AppendFramesToParent(nsFrameConstructorState&       aState,
                                             nsIFrame*                      aParentFrame,
                                             nsFrameItems&                  aFrameList,
                                             nsIFrame*                      aPrevSibling,
                                             bool                           aIsRecursiveCall)
 {
   NS_PRECONDITION(!IsFramePartOfIBSplit(aParentFrame) ||
                   !GetIBSplitSibling(aParentFrame) ||
                   !GetIBSplitSibling(aParentFrame)->GetFirstPrincipalChild(),
                   "aParentFrame has a ib-split sibling with kids?");
   NS_PRECONDITION(!aPrevSibling || aPrevSibling->GetParent() == aParentFrame,
                   "Parent and prevsibling don't match");
   nsIFrame* nextSibling = ::GetInsertNextSibling(aParentFrame, aPrevSibling);
   NS_ASSERTION(nextSibling ||
                !aParentFrame->GetNextContinuation() ||
                !aParentFrame->GetNextContinuation()->GetFirstPrincipalChild() ||
                aIsRecursiveCall,
                "aParentFrame has later continuations with kids?");
   NS_ASSERTION(nextSibling ||
                !IsFramePartOfIBSplit(aParentFrame) ||
                (IsInlineFrame(aParentFrame) &&
                 !GetIBSplitSibling(aParentFrame) &&
                 !aParentFrame->GetNextContinuation()) ||
                aIsRecursiveCall,
                "aParentFrame is not last?");
   // If we're inserting a list of frames at the end of the trailing inline
   // of an {ib} split, we may need to create additional {ib} siblings to parent
   // them.
   if (!nextSibling && IsFramePartOfIBSplit(aParentFrame)) {
     // When we get here, our frame list might start with a block.  If it does
     // so, and aParentFrame is an inline, and it and all its previous
     // continuations have no siblings, then put the initial blocks from the
     // frame list into the previous block of the {ib} split.  Note that we
     // didn't want to stop at the block part of the split when figuring out
     // initial parent, because that could screw up float parenting; it's easier
     // to do this little fixup here instead.
     if (aFrameList.NotEmpty() && !aFrameList.FirstChild()->IsInlineOutside()) {
       // See whether our trailing inline is empty
       nsIFrame* firstContinuation = aParentFrame->FirstContinuation();
       if (firstContinuation->PrincipalChildList().IsEmpty()) {
         // Our trailing inline is empty.  Collect our starting blocks from
         // aFrameList, get the right parent frame for them, and put them in.
         nsFrameList::FrameLinkEnumerator firstNonBlockEnumerator =
           FindFirstNonBlock(aFrameList);
         nsFrameList blockKids = aFrameList.ExtractHead(firstNonBlockEnumerator);
         NS_ASSERTION(blockKids.NotEmpty(), "No blocks?");
         nsIFrame* prevBlock =
           GetIBSplitPrevSibling(firstContinuation)->LastContinuation();
         NS_ASSERTION(prevBlock, "Should have previous block here");
         MoveChildrenTo(aState.mPresContext, aParentFrame, prevBlock, blockKids);
       }
     }
     // We want to put some of the frames into this inline frame.
     nsFrameList::FrameLinkEnumerator firstBlockEnumerator(aFrameList);
     FindFirstBlock(firstBlockEnumerator);
     nsFrameList inlineKids = aFrameList.ExtractHead(firstBlockEnumerator);
     if (!inlineKids.IsEmpty()) {
       AppendFrames(aParentFrame, kPrincipalList, inlineKids);
     }
     if (!aFrameList.IsEmpty()) {
       bool positioned = aParentFrame->IsRelativelyPositioned();
       nsFrameItems ibSiblings;
       CreateIBSiblings(aState, aParentFrame, positioned, aFrameList,
                        ibSiblings);
       // Make sure to trigger reflow of the inline that used to be our
       // last one and now isn't anymore, since its GetSkipSides() has
       // changed.
       mPresShell->FrameNeedsReflow(aParentFrame,
                                    nsIPresShell::eTreeChange,
                                    NS_FRAME_HAS_DIRTY_CHILDREN);
       // Recurse so we create new ib siblings as needed for aParentFrame's parent
       return AppendFramesToParent(aState, aParentFrame->GetParent(), ibSiblings,
                                   aParentFrame, true);
     }
     return NS_OK;
   }
   // Insert the frames after our aPrevSibling
   return InsertFrames(aParentFrame, kPrincipalList, aPrevSibling, aFrameList);
 }
 #define UNSET_DISPLAY 255
 // This gets called to see if the frames corresponding to aSibling and aContent
 // should be siblings in the frame tree. Although (1) rows and cols, (2) row
 // groups and col groups, (3) row groups and captions, (4) legends and content
 // inside fieldsets, (5) popups and other kids of the menu are siblings from a
 // content perspective, they are not considered siblings in the frame tree.
 bool
 nsCSSFrameConstructor::IsValidSibling(nsIFrame*              aSibling,
                                       nsIContent*            aContent,
                                       uint8_t&               aDisplay)
 {
   nsIFrame* parentFrame = aSibling->GetParent();
   nsIAtom* parentType = nullptr;
   if (parentFrame) {
     parentType = parentFrame->GetType();
   }
   uint8_t siblingDisplay = aSibling->GetDisplay();
   if ((NS_STYLE_DISPLAY_TABLE_COLUMN_GROUP == siblingDisplay) ||
       (NS_STYLE_DISPLAY_TABLE_COLUMN       == siblingDisplay) ||
       (NS_STYLE_DISPLAY_TABLE_CAPTION      == siblingDisplay) ||
       (NS_STYLE_DISPLAY_TABLE_HEADER_GROUP == siblingDisplay) ||
       (NS_STYLE_DISPLAY_TABLE_ROW_GROUP    == siblingDisplay) ||
       (NS_STYLE_DISPLAY_TABLE_FOOTER_GROUP == siblingDisplay) ||
       nsGkAtoms::menuFrame == parentType) {
     // if we haven't already, construct a style context to find the display type of aContent
     if (UNSET_DISPLAY == aDisplay) {
       nsRefPtr<nsStyleContext> styleContext;
       nsIFrame* styleParent = aSibling->GetParentStyleContextFrame();
       if (!styleParent) {
         NS_NOTREACHED("Shouldn't happen");
         return false;
       }
       // XXXbz when this code is killed, the state argument to
       // ResolveStyleContext can be made non-optional.
       styleContext = ResolveStyleContext(styleParent, aContent, nullptr);
       const nsStyleDisplay* display = styleContext->StyleDisplay();
       aDisplay = display->mDisplay;
     }
     if (nsGkAtoms::menuFrame == parentType) {
       return
         (NS_STYLE_DISPLAY_POPUP == aDisplay) ==
         (NS_STYLE_DISPLAY_POPUP == siblingDisplay);
     }
     // To have decent performance we want to return false in cases in which
     // reordering the two siblings has no effect on display.  To ensure
     // correctness, we MUST return false in cases where the two siblings have
     // the same desired parent type and live on different display lists.
     // Specificaly, columns and column groups should only consider columns and
     // column groups as valid siblings.  Captions should only consider other
     // captions.  All other things should consider each other as valid
     // siblings.  The restriction in the |if| above on siblingDisplay is ok,
     // because for correctness the only part that really needs to happen is to
     // not consider captions, column groups, and row/header/footer groups
     // siblings of each other.  Treating a column or colgroup as a valid
     // sibling of a non-table-related frame will just mean we end up reframing.
     if ((siblingDisplay == NS_STYLE_DISPLAY_TABLE_CAPTION) !=
         (aDisplay == NS_STYLE_DISPLAY_TABLE_CAPTION)) {
       // One's a caption and the other is not.  Not valid siblings.
       return false;
     }
     if ((siblingDisplay == NS_STYLE_DISPLAY_TABLE_COLUMN_GROUP ||
          siblingDisplay == NS_STYLE_DISPLAY_TABLE_COLUMN) !=
         (aDisplay == NS_STYLE_DISPLAY_TABLE_COLUMN_GROUP ||
          aDisplay == NS_STYLE_DISPLAY_TABLE_COLUMN)) {
       // One's a column or column group and the other is not.  Not valid
       // siblings.
       return false;
     }
     // Fall through; it's possible that the display type was overridden and
     // a different sort of frame was constructed, so we may need to return false
     // below.
   }
   if (IsFrameForFieldSet(parentFrame, parentType)) {
     // Legends can be sibling of legends but not of other content in the fieldset
     nsIAtom* sibType = aSibling->GetContentInsertionFrame()->GetType();
     bool legendContent = aContent->IsHTML(nsGkAtoms::legend);
     if ((legendContent  && (nsGkAtoms::legendFrame != sibType)) ||
         (!legendContent && (nsGkAtoms::legendFrame == sibType)))
       return false;
   }
   return true;
 }
 nsIFrame*
 nsCSSFrameConstructor::FindFrameForContentSibling(nsIContent* aContent,
                                                   nsIContent* aTargetContent,
                                                   uint8_t& aTargetContentDisplay,
                                                   bool aPrevSibling)
 {
   nsIFrame* sibling = aContent->GetPrimaryFrame();
   if (!sibling || sibling->GetContent() != aContent) {
     // XXX the GetContent() != aContent check is needed due to bug 135040.
     // Remove it once that's fixed.
     return nullptr;
   }
   // If the frame is out-of-flow, GetPrimaryFrame() will have returned the
   // out-of-flow frame; we want the placeholder.
   if (sibling->GetStateBits() & NS_FRAME_OUT_OF_FLOW) {
     nsIFrame* placeholderFrame = GetPlaceholderFrameFor(sibling);
     NS_ASSERTION(placeholderFrame, "no placeholder for out-of-flow frame");
     sibling = placeholderFrame;
   }
   // The frame we have now should never be a continuation
   NS_ASSERTION(!sibling->GetPrevContinuation(), "How did that happen?");
   if (aPrevSibling) {
     // The frame may be a ib-split frame (a split inline frame that
     // contains a block).  Get the last part of that split.
     if (IsFramePartOfIBSplit(sibling)) {
       sibling = GetLastIBSplitSibling(sibling, true);
     }
     // The frame may have a continuation. If so, we want the last
     // non-overflow-container continuation as our previous sibling.
     sibling = sibling->GetTailContinuation();
   }
   if (aTargetContent &&
       !IsValidSibling(sibling, aTargetContent, aTargetContentDisplay)) {
     sibling = nullptr;
   }
   return sibling;
 }
 nsIFrame*
 nsCSSFrameConstructor::FindPreviousSibling(FlattenedChildIterator aIter,
                                            uint8_t& aTargetContentDisplay)
 {
   nsIContent* child = aIter.Get();
   // Note: not all content objects are associated with a frame (e.g., if it's
   // `display: none') so keep looking until we find a previous frame
   while (nsIContent* sibling = aIter.GetPreviousChild()) {
     nsIFrame* prevSibling =
       FindFrameForContentSibling(sibling, child, aTargetContentDisplay, true);
     if (prevSibling) {
       // Found a previous sibling, we're done!
       return prevSibling;
     }
   }
   return nullptr;
 }
 nsIFrame*
 nsCSSFrameConstructor::FindNextSibling(FlattenedChildIterator aIter,
                                        uint8_t& aTargetContentDisplay)
 {
   nsIContent* child = aIter.Get();
   while (nsIContent* sibling = aIter.GetNextChild()) {
     nsIFrame* nextSibling =
       FindFrameForContentSibling(sibling, child, aTargetContentDisplay, false);
     if (nextSibling) {
       // We found a next sibling, we're done!
       return nextSibling;
     }
   }
   return nullptr;
 }
 // For fieldsets, returns the area frame, if the child is not a legend.
 static nsIFrame*
 GetAdjustedParentFrame(nsIFrame*       aParentFrame,
                        nsIAtom*        aParentFrameType,
                        nsIContent*     aChildContent)
 {
   NS_PRECONDITION(nsGkAtoms::tableOuterFrame != aParentFrameType,
                   "Shouldn't be happening!");
   nsIFrame* newParent = nullptr;
   if (nsGkAtoms::fieldSetFrame == aParentFrameType) {
     // If the parent is a fieldSet, use the fieldSet's area frame as the
     // parent unless the new content is a legend.
     if (!aChildContent->IsHTML(nsGkAtoms::legend)) {
       newParent = GetFieldSetBlockFrame(aParentFrame);
     }
   }
   return (newParent) ? newParent : aParentFrame;
 }
 nsIFrame*
 nsCSSFrameConstructor::GetInsertionPrevSibling(nsIFrame*& aParentFrame,
                                                nsIContent* aContainer,
                                                nsIContent* aChild,
                                                bool* aIsAppend,
                                                bool* aIsRangeInsertSafe,
                                                nsIContent* aStartSkipChild,
                                                nsIContent* aEndSkipChild)
 {
   *aIsAppend = false;
   // Find the frame that precedes the insertion point. Walk backwards
   // from the parent frame to get the parent content, because if an
   // XBL insertion point is involved, we'll need to use _that_ to find
   // the preceding frame.
   NS_PRECONDITION(aParentFrame, "Must have parent frame to start with");
   nsIContent* container = aParentFrame->GetContent();
   FlattenedChildIterator iter(container);
   bool xblCase = iter.XBLInvolved() || container != aContainer;
   if (xblCase || !aChild->IsRootOfAnonymousSubtree()) {
     // The check for IsRootOfAnonymousSubtree() is because editor is
     // severely broken and calls us directly for native anonymous
     // nodes that it creates.
     if (aStartSkipChild) {
       iter.Seek(aStartSkipChild);
     } else {
       iter.Seek(aChild);
     }
   } else {
     // Prime the iterator for the call to FindPreviousSibling.
     iter.GetNextChild();
     NS_WARNING("Someone passed native anonymous content directly into frame "
                "construction.  Stop doing that!");
   }
   // Note that FindPreviousSibling is passed the iterator by value, so that
   // the later usage of the iterator starts from the same place.
   uint8_t childDisplay = UNSET_DISPLAY;
   nsIFrame* prevSibling = FindPreviousSibling(iter, childDisplay);
   // Now, find the geometric parent so that we can handle
   // continuations properly. Use the prev sibling if we have it;
   // otherwise use the next sibling.
   if (prevSibling) {
     aParentFrame = prevSibling->GetParent()->GetContentInsertionFrame();
   }
   else {
     // If there is no previous sibling, then find the frame that follows
     if (aEndSkipChild) {
       iter.Seek(aEndSkipChild);
       iter.GetPreviousChild();
     }
     nsIFrame* nextSibling = FindNextSibling(iter, childDisplay);
     if (nextSibling) {
       aParentFrame = nextSibling->GetParent()->GetContentInsertionFrame();
     }
     else {
       // No previous or next sibling, so treat this like an appended frame.
       *aIsAppend = true;
       if (IsFramePartOfIBSplit(aParentFrame)) {
         // Since we're appending, we'll walk to the last anonymous frame
         // that was created for the broken inline frame.  But don't walk
         // to the trailing inline if it's empty; stop at the block.
         aParentFrame = GetLastIBSplitSibling(aParentFrame, false);
       }
       // Get continuation that parents the last child.  This MUST be done
       // before the AdjustAppendParentForAfterContent call.
       aParentFrame = nsLayoutUtils::LastContinuationWithChild(aParentFrame);
       // Deal with fieldsets
       aParentFrame = ::GetAdjustedParentFrame(aParentFrame,
                                               aParentFrame->GetType(),
                                               aChild);
       nsIFrame* appendAfterFrame;
       aParentFrame =
         ::AdjustAppendParentForAfterContent(mPresShell->GetPresContext(),
                                             container, aParentFrame,
                                             &appendAfterFrame);
       prevSibling = ::FindAppendPrevSibling(aParentFrame, appendAfterFrame);
     }
   }
   *aIsRangeInsertSafe = (childDisplay == UNSET_DISPLAY);
   return prevSibling;
 }
 static bool
 IsSpecialFramesetChild(nsIContent* aContent)
 {
   // IMPORTANT: This must match the conditions in nsHTMLFramesetFrame::Init.
   return aContent->IsHTML() &&
     (aContent->Tag() == nsGkAtoms::frameset ||
      aContent->Tag() == nsGkAtoms::frame);
 }
 static void
 InvalidateCanvasIfNeeded(nsIPresShell* presShell, nsIContent* node);
 #ifdef MOZ_XUL
 static
 bool
 IsXULListBox(nsIContent* aContainer)
 {
   return (aContainer->IsXUL() && aContainer->Tag() == nsGkAtoms::listbox);
 }
 static
 nsListBoxBodyFrame*
 MaybeGetListBoxBodyFrame(nsIContent* aContainer, nsIContent* aChild)
 {
   if (!aContainer)
     return nullptr;
   if (IsXULListBox(aContainer) &&
       aChild->IsXUL() && aChild->Tag() == nsGkAtoms::listitem) {
     nsCOMPtr<nsIDOMXULElement> xulElement = do_QueryInterface(aContainer);
     nsCOMPtr<nsIBoxObject> boxObject;
     xulElement->GetBoxObject(getter_AddRefs(boxObject));
     nsCOMPtr<nsPIListBoxObject> listBoxObject = do_QueryInterface(boxObject);
     if (listBoxObject) {
       return listBoxObject->GetListBoxBody(false);
     }
   }
   return nullptr;
 }
 #endif
 void
 nsCSSFrameConstructor::AddTextItemIfNeeded(nsFrameConstructorState& aState,
                                            nsIFrame* aParentFrame,
                                            nsIContent* aPossibleTextContent,
                                            FrameConstructionItemList& aItems)
 {
   NS_PRECONDITION(aPossibleTextContent, "Must have node");
   if (!aPossibleTextContent->IsNodeOfType(nsINode::eTEXT) ||
       !aPossibleTextContent->HasFlag(NS_CREATE_FRAME_IF_NON_WHITESPACE)) {
     // Not text, or not suppressed due to being all-whitespace (if it
     // were being suppressed, it would have the
     // NS_CREATE_FRAME_IF_NON_WHITESPACE flag)
     return;
   }
   NS_ASSERTION(!aPossibleTextContent->GetPrimaryFrame(),
                "Text node has a frame and NS_CREATE_FRAME_IF_NON_WHITESPACE");
   AddFrameConstructionItems(aState, aPossibleTextContent, false,
                             aParentFrame, aItems);
 }
 void
 nsCSSFrameConstructor::ReframeTextIfNeeded(nsIContent* aParentContent,
                                            nsIContent* aContent)
 {
   if (!aContent->IsNodeOfType(nsINode::eTEXT) ||
       !aContent->HasFlag(NS_CREATE_FRAME_IF_NON_WHITESPACE)) {
     // Not text, or not suppressed due to being all-whitespace (if it
     // were being suppressed, it would have the
     // NS_CREATE_FRAME_IF_NON_WHITESPACE flag)
     return;
   }
   NS_ASSERTION(!aContent->GetPrimaryFrame(),
                "Text node has a frame and NS_CREATE_FRAME_IF_NON_WHITESPACE");
   ContentInserted(aParentContent, aContent, nullptr, false);
 }
 // For inserts aChild should be valid, for appends it should be null.
 // Returns true if this operation can be lazy, false if not.
 bool
 nsCSSFrameConstructor::MaybeConstructLazily(Operation aOperation,
                                             nsIContent* aContainer,
                                             nsIContent* aChild)
 {
   if (mPresShell->GetPresContext()->IsChrome() || !aContainer ||
       aContainer->IsInNativeAnonymousSubtree() || aContainer->IsXUL()) {
     return false;
   }
   if (aOperation == CONTENTINSERT) {
     if (aChild->IsRootOfAnonymousSubtree() ||
         aChild->HasFlag(NODE_IS_IN_SHADOW_TREE) ||
         aChild->IsEditable() || aChild->IsXUL()) {
       return false;
     }
   } else { // CONTENTAPPEND
     NS_ASSERTION(aOperation == CONTENTAPPEND,
                  "operation should be either insert or append");
     for (nsIContent* child = aChild; child; child = child->GetNextSibling()) {
       NS_ASSERTION(!child->IsRootOfAnonymousSubtree(),
                    "Should be coming through the CONTENTAPPEND case");
       if (child->IsXUL() || child->IsEditable()) {
         return false;
       }
     }
   }
   // We can construct lazily; just need to set suitable bits in the content
   // tree.
   // Walk up the tree setting the NODE_DESCENDANTS_NEED_FRAMES bit as we go.
   nsIContent* content = aContainer;
 #ifdef DEBUG
   // If we hit a node with no primary frame, or the NODE_NEEDS_FRAME bit set
   // we want to assert, but leaf frames that process their own children and may
   // ignore anonymous children (eg framesets) make this complicated. So we set
   // these two booleans if we encounter these situations and unset them if we
   // hit a node with a leaf frame.
   bool noPrimaryFrame = false;
   bool needsFrameBitSet = false;
 #endif
   while (content &&
          !content->HasFlag(NODE_DESCENDANTS_NEED_FRAMES)) {
 #ifdef DEBUG
     if (content->GetPrimaryFrame() && content->GetPrimaryFrame()->IsLeaf()) {
       noPrimaryFrame = needsFrameBitSet = false;
     }
     if (!noPrimaryFrame && !content->GetPrimaryFrame()) {
       noPrimaryFrame = true;
     }
     if (!needsFrameBitSet && content->HasFlag(NODE_NEEDS_FRAME)) {
       needsFrameBitSet = true;
     }
 #endif
     content->SetFlags(NODE_DESCENDANTS_NEED_FRAMES);
     content = content->GetFlattenedTreeParent();
   }
 #ifdef DEBUG
   if (content && content->GetPrimaryFrame() &&
       content->GetPrimaryFrame()->IsLeaf()) {
     noPrimaryFrame = needsFrameBitSet = false;
   }
   NS_ASSERTION(!noPrimaryFrame, "Ancestors of nodes with frames to be "
     "constructed lazily should have frames");
   NS_ASSERTION(!needsFrameBitSet, "Ancestors of nodes with frames to be "
     "constructed lazily should not have NEEDS_FRAME bit set");
 #endif
   // Set NODE_NEEDS_FRAME on the new nodes.
   if (aOperation == CONTENTINSERT) {
     NS_ASSERTION(!aChild->GetPrimaryFrame() ||
                  aChild->GetPrimaryFrame()->GetContent() != aChild,
                  //XXX the aChild->GetPrimaryFrame()->GetContent() != aChild
                  // check is needed due to bug 135040. Remove it once that's
                  // fixed.
                  "setting NEEDS_FRAME on a node that already has a frame?");
     aChild->SetFlags(NODE_NEEDS_FRAME);
   } else { // CONTENTAPPEND
     for (nsIContent* child = aChild; child; child = child->GetNextSibling()) {
       NS_ASSERTION(!child->GetPrimaryFrame() ||
                    child->GetPrimaryFrame()->GetContent() != child,
                    //XXX the child->GetPrimaryFrame()->GetContent() != child
                    // check is needed due to bug 135040. Remove it once that's
                    // fixed.
                    "setting NEEDS_FRAME on a node that already has a frame?");
       child->SetFlags(NODE_NEEDS_FRAME);
     }
   }
   RestyleManager()->PostRestyleEventForLazyConstruction();
   return true;
 }
 void
 nsCSSFrameConstructor::CreateNeededFrames(nsIContent* aContent)
 {
   NS_ASSERTION(!aContent->HasFlag(NODE_NEEDS_FRAME),
     "shouldn't get here with a content node that has needs frame bit set");
   NS_ASSERTION(aContent->HasFlag(NODE_DESCENDANTS_NEED_FRAMES),
     "should only get here with a content node that has descendants needing frames");
   aContent->UnsetFlags(NODE_DESCENDANTS_NEED_FRAMES);
   // We could either descend first (on nodes that don't have NODE_NEEDS_FRAME
   // set) or issue content notifications for our kids first. In absence of
   // anything definitive either way we'll go with the latter.
   // It might be better to use GetChildArray and scan it completely first and
   // then issue all notifications. (We have to scan it completely first because
   // constructing frames can set attributes, which can change the storage of
   // child lists).
   // Scan the children of aContent to see what operations (if any) we need to
   // perform.
   uint32_t childCount = aContent->GetChildCount();
   bool inRun = false;
   nsIContent* firstChildInRun = nullptr;
   for (uint32_t i = 0; i < childCount; i++) {
     nsIContent* child = aContent->GetChildAt(i);
     if (child->HasFlag(NODE_NEEDS_FRAME)) {
       NS_ASSERTION(!child->GetPrimaryFrame() ||
                    child->GetPrimaryFrame()->GetContent() != child,
                    //XXX the child->GetPrimaryFrame()->GetContent() != child
                    // check is needed due to bug 135040. Remove it once that's
                    // fixed.
                    "NEEDS_FRAME set on a node that already has a frame?");
       if (!inRun) {
         inRun = true;
         firstChildInRun = child;
       }
     } else {
       if (inRun) {
         inRun = false;
         // generate a ContentRangeInserted for [startOfRun,i)
         ContentRangeInserted(aContent, firstChildInRun, child, nullptr,
                              false);
       }
     }
   }
   if (inRun) {
     ContentAppended(aContent, firstChildInRun, false);
   }
   // Now descend.
   FlattenedChildIterator iter(aContent);
   for (nsIContent* child = iter.GetNextChild(); child; child = iter.GetNextChild()) {
     if (child->HasFlag(NODE_DESCENDANTS_NEED_FRAMES)) {
       CreateNeededFrames(child);
     }
   }
 }
 void nsCSSFrameConstructor::CreateNeededFrames()
 {
   NS_ASSERTION(!nsContentUtils::IsSafeToRunScript(),
                "Someone forgot a script blocker");
   Element* rootElement = mDocument->GetRootElement();
   NS_ASSERTION(!rootElement || !rootElement->HasFlag(NODE_NEEDS_FRAME),
     "root element should not have frame created lazily");
   if (rootElement && rootElement->HasFlag(NODE_DESCENDANTS_NEED_FRAMES)) {
     BeginUpdate();
     CreateNeededFrames(rootElement);
     EndUpdate();
   }
 }
 void
 nsCSSFrameConstructor::IssueSingleInsertNofications(nsIContent* aContainer,
                                                     nsIContent* aStartChild,
                                                     nsIContent* aEndChild,
                                                     bool aAllowLazyConstruction)
 {
   for (nsIContent* child = aStartChild;
        child != aEndChild;
        child = child->GetNextSibling()) {
     if ((child->GetPrimaryFrame() ||
          GetUndisplayedContent(child))
 #ifdef MOZ_XUL
         //  Except listboxes suck, so do NOT skip anything here if
         //  we plan to notify a listbox.
         && !MaybeGetListBoxBodyFrame(aContainer, child)
 #endif
         ) {
       // Already have a frame or undisplayed entry for this content; a
       // previous ContentInserted in this loop must have reconstructed
       // its insertion parent.  Skip it.
       continue;
     }
     // Call ContentInserted with this node.
     ContentInserted(aContainer, child, mTempFrameTreeState,
                     aAllowLazyConstruction);
   }
 }
 nsIFrame*
 nsCSSFrameConstructor::GetRangeInsertionPoint(nsIContent* aContainer,
                                               nsIContent* aStartChild,
                                               nsIContent* aEndChild,
                                               bool aAllowLazyConstruction)
 {
   // See if we have an XBL insertion point. If so, then that's our
   // real parent frame; if not, then the frame hasn't been built yet
   // and we just bail.
   bool multiple = false;
   nsIFrame* insertionPoint = GetInsertionPoint(aContainer, nullptr, &multiple);
   if (!insertionPoint && !multiple)
     return nullptr; // Don't build the frames.
   bool hasInsertion = false;
   if (!multiple) {
     // XXXbz XBL2/sXBL issue
     nsIDocument* document = aStartChild->GetDocument();
     // XXXbz how would |document| be null here?
     if (document && aStartChild->GetXBLInsertionParent()) {
       hasInsertion = true;
     }
   }
   if (multiple || hasInsertion) {
     // We have an insertion point.  There are some additional tests we need to do
     // in order to ensure that an append is a safe operation.
     uint32_t childCount = 0;
     if (!multiple) {
       // We may need to make multiple ContentInserted calls instead.  A
       // reasonable heuristic to employ (in order to maintain good performance)
       // is to find out if the insertion point's content node contains any
       // explicit children.  If it does not, then it is highly likely that
       // an append is occurring.  (Note it is not definite, and there are insane
       // cases we will not deal with by employing this heuristic, but it beats
       // always falling back to multiple ContentInserted calls).
       //
       // In the multiple insertion point case, we know we're going to need to do
       // multiple ContentInserted calls anyway.
       // XXXndeakin This test doesn't work in the new world. Or rather, it works, but
       // it's slow
       childCount = insertionPoint->GetContent()->GetChildCount();
     }
     // If we have multiple insertion points or if we have an insertion point
     // and the operation is not a true append or if the insertion point already
     // has explicit children, then we must fall back.
     if (multiple || aEndChild != nullptr || childCount > 0) {
       // Now comes the fun part.  For each inserted child, make a
       // ContentInserted call as if it had just gotten inserted and
       // let ContentInserted handle the mess.
       IssueSingleInsertNofications(aContainer, aStartChild, aEndChild,
                                    aAllowLazyConstruction);
       return nullptr;
     }
   }
   return insertionPoint;
 }
 bool
 nsCSSFrameConstructor::MaybeRecreateForFrameset(nsIFrame* aParentFrame,
                                                 nsIContent* aStartChild,
                                                 nsIContent* aEndChild)
 {
   if (aParentFrame->GetType() == nsGkAtoms::frameSetFrame) {
     // Check whether we have any kids we care about.
     for (nsIContent* cur = aStartChild;
          cur != aEndChild;
          cur = cur->GetNextSibling()) {
       if (IsSpecialFramesetChild(cur)) {
         // Just reframe the parent, since framesets are weird like that.
         RecreateFramesForContent(aParentFrame->GetContent(), false);
         return true;
       }
     }
   }
   return false;
 }
 nsresult
 nsCSSFrameConstructor::ContentAppended(nsIContent*     aContainer,
                                        nsIContent*     aFirstNewContent,
                                        bool            aAllowLazyConstruction)
 {
   AUTO_LAYOUT_PHASE_ENTRY_POINT(mPresShell->GetPresContext(), FrameC);
   NS_PRECONDITION(mUpdateCount != 0,
                   "Should be in an update while creating frames");
 #ifdef DEBUG
   if (gNoisyContentUpdates) {
     printf("nsCSSFrameConstructor::ContentAppended container=%p "
            "first-child=%p lazy=%d\n",
            static_cast<void*>(aContainer), aFirstNewContent,
            aAllowLazyConstruction);
     if (gReallyNoisyContentUpdates && aContainer) {
       aContainer->List(stdout, 0);
     }
   }
 #endif
 #ifdef DEBUG
   for (nsIContent* child = aFirstNewContent;
        child;
        child = child->GetNextSibling()) {
     // XXX the GetContent() != child check is needed due to bug 135040.
     // Remove it once that's fixed.
     NS_ASSERTION(!child->GetPrimaryFrame() ||
                  child->GetPrimaryFrame()->GetContent() != child,
                  "asked to construct a frame for a node that already has a frame");
   }
 #endif
 #ifdef MOZ_XUL
   if (aContainer) {
     int32_t namespaceID;
     nsIAtom* tag =
       mDocument->BindingManager()->ResolveTag(aContainer, &namespaceID);
     // Just ignore tree tags, anyway we don't create any frames for them.
     if (tag == nsGkAtoms::treechildren ||
         tag == nsGkAtoms::treeitem ||
         tag == nsGkAtoms::treerow)
       return NS_OK;
   }
 #endif // MOZ_XUL
   if (aContainer && aContainer->HasFlag(NODE_IS_IN_SHADOW_TREE)) {
     // Recreate frames if content is appended into a ShadowRoot
     // because children of ShadowRoot are rendered in place of children
     // of the host.
     nsIContent* bindingParent = aContainer->GetBindingParent();
     LAYOUT_PHASE_TEMP_EXIT();
     nsresult rv = RecreateFramesForContent(bindingParent, false);
     LAYOUT_PHASE_TEMP_REENTER();
     return rv;
   }
   // Get the frame associated with the content
   nsIFrame* parentFrame = GetFrameFor(aContainer);
   // See comment in ContentRangeInserted for why this is necessary.
   if (!parentFrame && !aContainer->IsActiveChildrenElement()) {
     return NS_OK;
   }
   if (aAllowLazyConstruction &&
       MaybeConstructLazily(CONTENTAPPEND, aContainer, aFirstNewContent)) {
     return NS_OK;
   }
   LAYOUT_PHASE_TEMP_EXIT();
   parentFrame = GetRangeInsertionPoint(aContainer,
                                        aFirstNewContent, nullptr,
                                        aAllowLazyConstruction);
   LAYOUT_PHASE_TEMP_REENTER();
   if (!parentFrame) {
     return NS_OK;
   }
   LAYOUT_PHASE_TEMP_EXIT();
   if (MaybeRecreateForFrameset(parentFrame, aFirstNewContent, nullptr)) {
     LAYOUT_PHASE_TEMP_REENTER();
     return NS_OK;
   }
   LAYOUT_PHASE_TEMP_REENTER();
   if (parentFrame->IsLeaf()) {
     // Nothing to do here; we shouldn't be constructing kids of leaves
     // Clear lazy bits so we don't try to construct again.
     ClearLazyBits(aFirstNewContent, nullptr);
     return NS_OK;
   }
   if (parentFrame->IsFrameOfType(nsIFrame::eMathML)) {
     LAYOUT_PHASE_TEMP_EXIT();
     nsresult rv = RecreateFramesForContent(parentFrame->GetContent(), false);
     LAYOUT_PHASE_TEMP_REENTER();
     return rv;
   }
   // If the frame we are manipulating is a ib-split frame (that is, one
   // that's been created as a result of a block-in-inline situation) then we
   // need to append to the last ib-split sibling, not to the frame itself.
   bool parentIBSplit = IsFramePartOfIBSplit(parentFrame);
   if (parentIBSplit) {
 #ifdef DEBUG
     if (gNoisyContentUpdates) {
       printf("nsCSSFrameConstructor::ContentAppended: parentFrame=");
       nsFrame::ListTag(stdout, parentFrame);
       printf(" is ib-split\n");
     }
 #endif
     // Since we're appending, we'll walk to the last anonymous frame
     // that was created for the broken inline frame.  But don't walk
     // to the trailing inline if it's empty; stop at the block.
     parentFrame = GetLastIBSplitSibling(parentFrame, false);
   }
   // Get continuation that parents the last child.  This MUST be done
   // before the AdjustAppendParentForAfterContent call.
   parentFrame = nsLayoutUtils::LastContinuationWithChild(parentFrame);
   // We should never get here with fieldsets, since they have multiple
   // insertion points.
   NS_ASSERTION(parentFrame->GetType() != nsGkAtoms::fieldSetFrame,
                "Unexpected parent");
   // Deal with possible :after generated content on the parent
   nsIFrame* parentAfterFrame;
   parentFrame =
     ::AdjustAppendParentForAfterContent(mPresShell->GetPresContext(),
                                         aContainer, parentFrame,
                                         &parentAfterFrame);
   // Create some new frames
   nsFrameConstructorState state(mPresShell,
                                 GetAbsoluteContainingBlock(parentFrame, FIXED_POS),
                                 GetAbsoluteContainingBlock(parentFrame, ABS_POS),
                                 GetFloatContainingBlock(parentFrame));
   state.mTreeMatchContext.InitAncestors(aContainer->AsElement());
   // See if the containing block has :first-letter style applied.
   bool haveFirstLetterStyle = false, haveFirstLineStyle = false;
   nsIFrame* containingBlock = state.mFloatedItems.containingBlock;
   if (containingBlock) {
     haveFirstLetterStyle = HasFirstLetterStyle(containingBlock);
     haveFirstLineStyle =
       ShouldHaveFirstLineStyle(containingBlock->GetContent(),
                                containingBlock->StyleContext());
   }
   if (haveFirstLetterStyle) {
     // Before we get going, remove the current letter frames
     RemoveLetterFrames(state.mPresContext, state.mPresShell,
                        containingBlock);
   }
   nsIAtom* frameType = parentFrame->GetType();
   FlattenedChildIterator iter(aContainer);
   bool haveNoXBLChildren = (!iter.XBLInvolved() || !iter.GetNextChild());
   FrameConstructionItemList items;
   if (aFirstNewContent->GetPreviousSibling() &&
       GetParentType(frameType) == eTypeBlock &&
       haveNoXBLChildren) {
     // If there's a text node in the normal content list just before the new
     // items, and it has no frame, make a frame construction item for it. If it
     // doesn't need a frame, ConstructFramesFromItemList below won't give it
     // one.  No need to do all this if our parent type is not block, though,
     // since WipeContainingBlock already handles that situation.
     //
     // Because we're appending, we don't need to worry about any text
     // after the appended content; there can only be XBL anonymous content
     // (text in an XBL binding is not suppressed) or generated content
     // (and bare text nodes are not generated). Native anonymous content
     // generated by frames never participates in inline layout.
     AddTextItemIfNeeded(state, parentFrame,
                         aFirstNewContent->GetPreviousSibling(), items);
   }
   for (nsIContent* child = aFirstNewContent;
        child;
        child = child->GetNextSibling()) {
     AddFrameConstructionItems(state, child, false, parentFrame, items);
   }
   nsIFrame* prevSibling = ::FindAppendPrevSibling(parentFrame, parentAfterFrame);
   // Perform special check for diddling around with the frames in
   // a ib-split inline frame.
   // If we're appending before :after content, then we're not really
   // appending, so let WipeContainingBlock know that.
   LAYOUT_PHASE_TEMP_EXIT();
   if (WipeContainingBlock(state, containingBlock, parentFrame, items,
                           true, prevSibling)) {
     LAYOUT_PHASE_TEMP_REENTER();
     return NS_OK;
   }
   LAYOUT_PHASE_TEMP_REENTER();
   // If the parent is a block frame, and we're not in a special case
   // where frames can be moved around, determine if the list is for the
   // start or end of the block.
   if (nsLayoutUtils::GetAsBlock(parentFrame) && !haveFirstLetterStyle &&
       !haveFirstLineStyle && !parentIBSplit) {
     items.SetLineBoundaryAtStart(!prevSibling ||
         !prevSibling->IsInlineOutside() ||
         prevSibling->GetType() == nsGkAtoms::brFrame);
     // :after content can't be <br> so no need to check it
     items.SetLineBoundaryAtEnd(!parentAfterFrame ||
         !parentAfterFrame->IsInlineOutside());
   }
   // To suppress whitespace-only text frames, we have to verify that
   // our container's DOM child list matches its flattened tree child list.
   items.SetParentHasNoXBLChildren(haveNoXBLChildren);
   nsFrameItems frameItems;
   ConstructFramesFromItemList(state, items, parentFrame, frameItems);
   for (nsIContent* child = aFirstNewContent;
        child;
        child = child->GetNextSibling()) {
     // Invalidate now instead of before the WipeContainingBlock call, just in
     // case we do wipe; in that case we don't need to do this walk at all.
     // XXXbz does that matter?  Would it make more sense to save some virtual
     // GetChildAt calls instead and do this during construction of our
     // FrameConstructionItemList?
     InvalidateCanvasIfNeeded(mPresShell, child);
   }
   // if the container is a table and a caption was appended, it needs to be put
   // in the outer table frame's additional child list.
   nsFrameItems captionItems;
   if (nsGkAtoms::tableFrame == frameType) {
     // Pull out the captions.  Note that we don't want to do that as we go,
     // because processing a single caption can add a whole bunch of things to
     // the frame items due to pseudoframe processing.  So we'd have to pull
     // captions from a list anyway; might as well do that here.
     // XXXbz this is no longer true; we could pull captions directly out of the
     // FrameConstructionItemList now.
     PullOutCaptionFrames(frameItems, captionItems);
   }
   if (haveFirstLineStyle && parentFrame == containingBlock) {
     // It's possible that some of the new frames go into a
     // first-line frame. Look at them and see...
     AppendFirstLineFrames(state, containingBlock->GetContent(),
                           containingBlock, frameItems);
   }
   // Notify the parent frame passing it the list of new frames
   // Append the flowed frames to the principal child list; captions
   // need special treatment
   if (captionItems.NotEmpty()) { // append the caption to the outer table
     NS_ASSERTION(nsGkAtoms::tableFrame == frameType, "how did that happen?");
     nsIFrame* outerTable = parentFrame->GetParent();
     AppendFrames(outerTable, nsIFrame::kCaptionList, captionItems);
   }
   if (frameItems.NotEmpty()) { // append the in-flow kids
     AppendFramesToParent(state, parentFrame, frameItems, prevSibling);
   }
   // Recover first-letter frames
   if (haveFirstLetterStyle) {
     RecoverLetterFrames(containingBlock);
   }
 #ifdef DEBUG
   if (gReallyNoisyContentUpdates) {
     printf("nsCSSFrameConstructor::ContentAppended: resulting frame model:\n");
     parentFrame->List(stdout, 0);
   }
 #endif
 #ifdef ACCESSIBILITY
   nsAccessibilityService* accService = nsIPresShell::AccService();
   if (accService) {
     accService->ContentRangeInserted(mPresShell, aContainer,
                                      aFirstNewContent, nullptr);
   }
 #endif
   return NS_OK;
 }
 #ifdef MOZ_XUL
 enum content_operation
 {
     CONTENT_INSERTED,
     CONTENT_REMOVED
 };
 // Helper function to lookup the listbox body frame and send a notification
 // for insertion or removal of content
 static
 bool NotifyListBoxBody(nsPresContext*    aPresContext,
                          nsIContent*        aContainer,
                          nsIContent*        aChild,
                          // Only used for the removed notification
                          nsIContent*        aOldNextSibling,
                          nsIDocument*       aDocument,
                          nsIFrame*          aChildFrame,
                          content_operation  aOperation)
 {
   nsListBoxBodyFrame* listBoxBodyFrame =
     MaybeGetListBoxBodyFrame(aContainer, aChild);
   if (listBoxBodyFrame) {
     if (aOperation == CONTENT_REMOVED) {
       // Except if we have an aChildFrame and its parent is not the right
       // thing, then we don't do this.  Pseudo frames are so much fun....
       if (!aChildFrame || aChildFrame->GetParent() == listBoxBodyFrame) {
         listBoxBodyFrame->OnContentRemoved(aPresContext, aContainer,
                                            aChildFrame, aOldNextSibling);
         return true;
       }
     } else {
       listBoxBodyFrame->OnContentInserted(aPresContext, aChild);
       return true;
     }
   }
   return false;
 }
 #endif // MOZ_XUL
 nsresult
 nsCSSFrameConstructor::ContentInserted(nsIContent*            aContainer,
                                        nsIContent*            aChild,
                                        nsILayoutHistoryState* aFrameState,
                                        bool                   aAllowLazyConstruction)
 {
   return ContentRangeInserted(aContainer,
                               aChild,
                               aChild->GetNextSibling(),
                               aFrameState,
                               aAllowLazyConstruction);
 }
 // ContentRangeInserted handles creating frames for a range of nodes that
 // aren't at the end of their childlist. ContentRangeInserted isn't a real
 // content notification, but rather it handles regular ContentInserted calls
 // for a single node as well as the lazy construction of frames for a range of
 // nodes when called from CreateNeededFrames. For a range of nodes to be
 // suitable to have its frames constructed all at once they must meet the same
 // conditions that ContentAppended imposes (GetRangeInsertionPoint checks
 // these), plus more. Namely when finding the insertion prevsibling we must not
 // need to consult something specific to any one node in the range, so that the
 // insertion prevsibling would be the same for each node in the range. So we
 // pass the first node in the range to GetInsertionPrevSibling, and if
 // IsValidSibling (the only place GetInsertionPrevSibling might look at the
 // passed in node itself) needs to resolve style on the node we record this and
 // return that this range needs to be split up and inserted separately. Table
 // captions need extra attention as we need to determine where to insert them
 // in the caption list, while skipping any nodes in the range being inserted
 // (because when we treat the caption frames the other nodes have had their
 // frames constructed but not yet inserted into the frame tree).
 nsresult
 nsCSSFrameConstructor::ContentRangeInserted(nsIContent*            aContainer,
                                             nsIContent*            aStartChild,
                                             nsIContent*            aEndChild,
                                             nsILayoutHistoryState* aFrameState,
                                             bool                   aAllowLazyConstruction)
 {
   AUTO_LAYOUT_PHASE_ENTRY_POINT(mPresShell->GetPresContext(), FrameC);
   NS_PRECONDITION(mUpdateCount != 0,
                   "Should be in an update while creating frames");
   NS_PRECONDITION(aStartChild, "must always pass a child");
   // XXXldb Do we need to re-resolve style to handle the CSS2 + combinator and
   // the :empty pseudo-class?
 #ifdef DEBUG
   if (gNoisyContentUpdates) {
     printf("nsCSSFrameConstructor::ContentRangeInserted container=%p "
            "start-child=%p end-child=%p lazy=%d\n",
            static_cast<void*>(aContainer),
            static_cast<void*>(aStartChild), static_cast<void*>(aEndChild),
            aAllowLazyConstruction);
     if (gReallyNoisyContentUpdates) {
       if (aContainer) {
         aContainer->List(stdout,0);
       } else {
         aStartChild->List(stdout, 0);
       }
     }
   }
 #endif
 #ifdef DEBUG
   for (nsIContent* child = aStartChild;
        child != aEndChild;
        child = child->GetNextSibling()) {
     // XXX the GetContent() != child check is needed due to bug 135040.
     // Remove it once that's fixed.
     NS_ASSERTION(!child->GetPrimaryFrame() ||
                  child->GetPrimaryFrame()->GetContent() != child,
                  "asked to construct a frame for a node that already has a frame");
   }
 #endif
   bool isSingleInsert = (aStartChild->GetNextSibling() == aEndChild);
   NS_ASSERTION(isSingleInsert || !aAllowLazyConstruction,
                "range insert shouldn't be lazy");
   NS_ASSERTION(isSingleInsert || aEndChild,
                "range should not include all nodes after aStartChild");
 #ifdef MOZ_XUL
   if (aContainer && IsXULListBox(aContainer)) {
     if (isSingleInsert) {
       if (NotifyListBoxBody(mPresShell->GetPresContext(), aContainer,
                             // The insert case in NotifyListBoxBody
                             // doesn't use "old next sibling".
                             aStartChild, nullptr,
                             mDocument, nullptr, CONTENT_INSERTED)) {
         return NS_OK;
       }
     } else {
       // We don't handle a range insert to a listbox parent, issue single
       // ContertInserted calls for each node inserted.
       LAYOUT_PHASE_TEMP_EXIT();
       IssueSingleInsertNofications(aContainer, aStartChild, aEndChild,
                                    aAllowLazyConstruction);
       LAYOUT_PHASE_TEMP_REENTER();
       return NS_OK;
     }
   }
 #endif // MOZ_XUL
   // If we have a null parent, then this must be the document element being
   // inserted, or some other child of the document in the DOM (might be a PI,
   // say).
   if (! aContainer) {
     NS_ASSERTION(isSingleInsert,
                  "root node insertion should be a single insertion");
     Element *docElement = mDocument->GetRootElement();
     if (aStartChild != docElement) {
       // Not the root element; just bail out
       return NS_OK;
     }
     NS_PRECONDITION(nullptr == mRootElementFrame,
                     "root element frame already created");
     // Create frames for the document element and its child elements
     nsIFrame* docElementFrame =
       ConstructDocElementFrame(docElement, aFrameState);
     if (docElementFrame) {
       InvalidateCanvasIfNeeded(mPresShell, aStartChild);
 #ifdef DEBUG
       if (gReallyNoisyContentUpdates) {
         printf("nsCSSFrameConstructor::ContentRangeInserted: resulting frame "
                "model:\n");
         mFixedContainingBlock->List(stdout, 0);
       }
 #endif
     }
     if (aFrameState) {
       // Restore frame state for the root scroll frame if there is one
       nsIFrame* rootScrollFrame = mPresShell->GetRootScrollFrame();
       if (rootScrollFrame) {
         RestoreFrameStateFor(rootScrollFrame, aFrameState);
       }
     }
 #ifdef ACCESSIBILITY
     nsAccessibilityService* accService = nsIPresShell::AccService();
     if (accService) {
       accService->ContentRangeInserted(mPresShell, aContainer,
                                        aStartChild, aEndChild);
     }
 #endif
     return NS_OK;
   }
   if (aContainer->HasFlag(NODE_IS_IN_SHADOW_TREE)) {
     // Recreate frames if content is inserted into a ShadowRoot
     // because children of ShadowRoot are rendered in place of
     // the children of the host.
     nsIContent* bindingParent = aContainer->GetBindingParent();
     LAYOUT_PHASE_TEMP_EXIT();
     nsresult rv = RecreateFramesForContent(bindingParent, false);
     LAYOUT_PHASE_TEMP_REENTER();
     return rv;
   }
   nsIFrame* parentFrame = GetFrameFor(aContainer);
   // The xbl:children element won't have a frame, but default content can have the children as
   // a parent. While its uncommon to change the structure of the default content itself, a label,
   // for example, can be reframed by having its value attribute set or removed.
   if (!parentFrame && !aContainer->IsActiveChildrenElement()) {
     return NS_OK;
   }
   // Otherwise, we've got parent content. Find its frame.
   NS_ASSERTION(!parentFrame || parentFrame->GetContent() == aContainer, "New XBL code is possibly wrong!");
   if (aAllowLazyConstruction &&
       MaybeConstructLazily(CONTENTINSERT, aContainer, aStartChild)) {
     return NS_OK;
   }
   if (isSingleInsert) {
     // See if we have an XBL insertion point. If so, then that's our
     // real parent frame; if not, then the frame hasn't been built yet
     // and we just bail.
     parentFrame = GetInsertionPoint(aContainer, aStartChild);
   } else {
     // Get our insertion point. If we need to issue single ContentInserted's
     // GetRangeInsertionPoint will take care of that for us.
     LAYOUT_PHASE_TEMP_EXIT();
     parentFrame = GetRangeInsertionPoint(aContainer, aStartChild, aEndChild,
                                          aAllowLazyConstruction);
     LAYOUT_PHASE_TEMP_REENTER();
   }
   if (!parentFrame) {
     return NS_OK;
   }
   bool isAppend, isRangeInsertSafe;
   nsIFrame* prevSibling =
     GetInsertionPrevSibling(parentFrame, aContainer, aStartChild,
                             &isAppend, &isRangeInsertSafe);
   // check if range insert is safe
   if (!isSingleInsert && !isRangeInsertSafe) {
     // must fall back to a single ContertInserted for each child in the range
     LAYOUT_PHASE_TEMP_EXIT();
     IssueSingleInsertNofications(aContainer, aStartChild, aEndChild,
                                  aAllowLazyConstruction);
     LAYOUT_PHASE_TEMP_REENTER();
     return NS_OK;
   }
   nsIContent* container = parentFrame->GetContent();
   nsIAtom* frameType = parentFrame->GetType();
   LAYOUT_PHASE_TEMP_EXIT();
   if (MaybeRecreateForFrameset(parentFrame, aStartChild, aEndChild)) {
     LAYOUT_PHASE_TEMP_REENTER();
     return NS_OK;
   }
   LAYOUT_PHASE_TEMP_REENTER();
   // We should only get here with fieldsets when doing a single insert, because
   // fieldsets have multiple insertion points.
   NS_ASSERTION(isSingleInsert || frameType != nsGkAtoms::fieldSetFrame,
                "Unexpected parent");
   if (IsFrameForFieldSet(parentFrame, frameType) &&
       aStartChild->Tag() == nsGkAtoms::legend) {
     // Just reframe the parent, since figuring out whether this
     // should be the new legend and then handling it is too complex.
     // We could do a little better here --- check if the fieldset already
     // has a legend which occurs earlier in its child list than this node,
     // and if so, proceed. But we'd have to extend nsFieldSetFrame
     // to locate this legend in the inserted frames and extract it.
     LAYOUT_PHASE_TEMP_EXIT();
     nsresult rv = RecreateFramesForContent(parentFrame->GetContent(), false);
     LAYOUT_PHASE_TEMP_REENTER();
     return rv;
   }
   // Don't construct kids of leaves
   if (parentFrame->IsLeaf()) {
     // Clear lazy bits so we don't try to construct again.
     ClearLazyBits(aStartChild, aEndChild);
     return NS_OK;
   }
   if (parentFrame->IsFrameOfType(nsIFrame::eMathML)) {
     LAYOUT_PHASE_TEMP_EXIT();
     nsresult rv = RecreateFramesForContent(parentFrame->GetContent(), false);
     LAYOUT_PHASE_TEMP_REENTER();
     return rv;
   }
   nsFrameConstructorState state(mPresShell,
                                 GetAbsoluteContainingBlock(parentFrame, FIXED_POS),
                                 GetAbsoluteContainingBlock(parentFrame, ABS_POS),
                                 GetFloatContainingBlock(parentFrame),
                                 aFrameState);
   state.mTreeMatchContext.InitAncestors(aContainer ?
                                           aContainer->AsElement() :
                                           nullptr);
   // Recover state for the containing block - we need to know if
   // it has :first-letter or :first-line style applied to it. The
   // reason we care is that the internal structure in these cases
   // is not the normal structure and requires custom updating
   // logic.
   nsIFrame* containingBlock = state.mFloatedItems.containingBlock;
   bool haveFirstLetterStyle = false;
   bool haveFirstLineStyle = false;
   // In order to shave off some cycles, we only dig up the
   // containing block haveFirst* flags if the parent frame where
   // the insertion/append is occurring is an inline or block
   // container. For other types of containers this isn't relevant.
   uint8_t parentDisplay = parentFrame->GetDisplay();
   // Examine the parentFrame where the insertion is taking
   // place. If it's a certain kind of container then some special
   // processing is done.
   if ((NS_STYLE_DISPLAY_BLOCK == parentDisplay) ||
       (NS_STYLE_DISPLAY_LIST_ITEM == parentDisplay) ||
       (NS_STYLE_DISPLAY_INLINE == parentDisplay) ||
       (NS_STYLE_DISPLAY_INLINE_BLOCK == parentDisplay)) {
     // Recover the special style flags for the containing block
     if (containingBlock) {
       haveFirstLetterStyle = HasFirstLetterStyle(containingBlock);
       haveFirstLineStyle =
         ShouldHaveFirstLineStyle(containingBlock->GetContent(),
                                  containingBlock->StyleContext());
     }
     if (haveFirstLetterStyle) {
       // If our current parentFrame is a Letter frame, use its parent as our
       // new parent hint
       if (parentFrame->GetType() == nsGkAtoms::letterFrame) {
         // If parentFrame is out of flow, then we actually want the parent of
         // the placeholder frame.
         if (parentFrame->GetStateBits() & NS_FRAME_OUT_OF_FLOW) {
           nsPlaceholderFrame* placeholderFrame =
             GetPlaceholderFrameFor(parentFrame);
           NS_ASSERTION(placeholderFrame, "No placeholder for out-of-flow?");
           parentFrame = placeholderFrame->GetParent();
         } else {
           parentFrame = parentFrame->GetParent();
         }
       }
       // Remove the old letter frames before doing the insertion
       RemoveLetterFrames(state.mPresContext, mPresShell,
                          state.mFloatedItems.containingBlock);
       // Removing the letterframes messes around with the frame tree, removing
       // and creating frames.  We need to reget our prevsibling, parent frame,
       // etc.
       prevSibling = GetInsertionPrevSibling(parentFrame, aContainer,
                                             aStartChild, &isAppend,
                                             &isRangeInsertSafe);
       // Need check whether a range insert is still safe.
       if (!isSingleInsert && !isRangeInsertSafe) {
         // Need to recover the letter frames first.
         RecoverLetterFrames(state.mFloatedItems.containingBlock);
         // must fall back to a single ContertInserted for each child in the range
         LAYOUT_PHASE_TEMP_EXIT();
         IssueSingleInsertNofications(aContainer, aStartChild, aEndChild,
                                      aAllowLazyConstruction);
         LAYOUT_PHASE_TEMP_REENTER();
         return NS_OK;
       }
       container = parentFrame->GetContent();
       frameType = parentFrame->GetType();
     }
   }
   if (!prevSibling) {
     // We're inserting the new frames as the first child. See if the
     // parent has a :before pseudo-element
     nsIFrame* firstChild = parentFrame->GetFirstPrincipalChild();
     if (firstChild &&
         nsLayoutUtils::IsGeneratedContentFor(container, firstChild,
                                              nsCSSPseudoElements::before)) {
       // Insert the new frames after the last continuation of the :before
       prevSibling = firstChild->GetTailContinuation();
       parentFrame = prevSibling->GetParent()->GetContentInsertionFrame();
       // Don't change isAppend here; we'll can call AppendFrames as needed, and
       // the change to our prevSibling doesn't affect that.
     }
   }
   FrameConstructionItemList items;
   ParentType parentType = GetParentType(frameType);
   FlattenedChildIterator iter(aContainer);
   bool haveNoXBLChildren = (!iter.XBLInvolved() || !iter.GetNextChild());
   if (aStartChild->GetPreviousSibling() &&
       parentType == eTypeBlock && haveNoXBLChildren) {
     // If there's a text node in the normal content list just before the
     // new nodes, and it has no frame, make a frame construction item for
     // it, because it might need a frame now.  No need to do this if our
     // parent type is not block, though, since WipeContainingBlock
     // already handles that sitation.
     AddTextItemIfNeeded(state, parentFrame, aStartChild->GetPreviousSibling(),
                         items);
   }
   if (isSingleInsert) {
     AddFrameConstructionItems(state, aStartChild,
                               aStartChild->IsRootOfAnonymousSubtree(),
                               parentFrame, items);
   } else {
     for (nsIContent* child = aStartChild;
          child != aEndChild;
          child = child->GetNextSibling()){
       AddFrameConstructionItems(state, child, false, parentFrame, items);
     }
   }
   if (aEndChild && parentType == eTypeBlock && haveNoXBLChildren) {
     // If there's a text node in the normal content list just after the
     // new nodes, and it has no frame, make a frame construction item for
     // it, because it might need a frame now.  No need to do this if our
     // parent type is not block, though, since WipeContainingBlock
     // already handles that sitation.
     AddTextItemIfNeeded(state, parentFrame, aEndChild, items);
   }
   // Perform special check for diddling around with the frames in
   // a special inline frame.
   // If we're appending before :after content, then we're not really
   // appending, so let WipeContainingBlock know that.
   LAYOUT_PHASE_TEMP_EXIT();
   if (WipeContainingBlock(state, containingBlock, parentFrame, items,
                           isAppend, prevSibling)) {
     LAYOUT_PHASE_TEMP_REENTER();
     return NS_OK;
   }
   LAYOUT_PHASE_TEMP_REENTER();
   // If the container is a table and a caption will be appended, it needs to be
   // put in the outer table frame's additional child list.
   // We make no attempt here to set flags to indicate whether the list
   // will be at the start or end of a block. It doesn't seem worthwhile.
   nsFrameItems frameItems, captionItems;
   ConstructFramesFromItemList(state, items, parentFrame, frameItems);
   if (frameItems.NotEmpty()) {
     for (nsIContent* child = aStartChild;
          child != aEndChild;
          child = child->GetNextSibling()){
       InvalidateCanvasIfNeeded(mPresShell, child);
     }
     if (nsGkAtoms::tableFrame == frameType ||
         nsGkAtoms::tableOuterFrame == frameType) {
       PullOutCaptionFrames(frameItems, captionItems);
     }
   }
   // If the parent of our current prevSibling is different from the frame we'll
   // actually use as the parent, then the calculated insertion point is now
   // invalid and as it is unknown where to insert correctly we append instead
   // (bug 341858).
   // This can affect our prevSibling and isAppend, but should not have any
   // effect on the WipeContainingBlock above, since this should only happen
   // when neither parent is a ib-split frame and should not affect whitespace
   // handling inside table-related frames (and in fact, can only happen when
   // one of the parents is an outer table and one is an inner table or when the
   // parent is a fieldset or fieldset content frame).  So it won't affect the
   // {ib} or XUL box cases in WipeContainingBlock(), and the table pseudo
   // handling will only be affected by us maybe thinking we're not inserting
   // at the beginning, whereas we really are.  That would have made us reframe
   // unnecessarily, but that's ok.
   // XXXbz we should push our frame construction item code up higher, so we
   // know what our items are by the time we start figuring out previous
   // siblings
   if (prevSibling && frameItems.NotEmpty() &&
       frameItems.FirstChild()->GetParent() != prevSibling->GetParent()) {
 #ifdef DEBUG
     nsIFrame* frame1 = frameItems.FirstChild()->GetParent();
     nsIFrame* frame2 = prevSibling->GetParent();
     NS_ASSERTION(!IsFramePartOfIBSplit(frame1) &&
                  !IsFramePartOfIBSplit(frame2),
                  "Neither should be ib-split");
     NS_ASSERTION((frame1->GetType() == nsGkAtoms::tableFrame &&
                   frame2->GetType() == nsGkAtoms::tableOuterFrame) ||
                  (frame1->GetType() == nsGkAtoms::tableOuterFrame &&
                   frame2->GetType() == nsGkAtoms::tableFrame) ||
                  frame1->GetType() == nsGkAtoms::fieldSetFrame ||
                  (frame1->GetParent() &&
                   frame1->GetParent()->GetType() == nsGkAtoms::fieldSetFrame),
                  "Unexpected frame types");
 #endif
     isAppend = true;
     nsIFrame* appendAfterFrame;
     parentFrame =
       ::AdjustAppendParentForAfterContent(mPresShell->GetPresContext(),
                                           container,
                                           frameItems.FirstChild()->GetParent(),
                                           &appendAfterFrame);
     prevSibling = ::FindAppendPrevSibling(parentFrame, appendAfterFrame);
   }
   if (haveFirstLineStyle && parentFrame == containingBlock) {
     // It's possible that the new frame goes into a first-line
     // frame. Look at it and see...
     if (isAppend) {
       // Use append logic when appending
       AppendFirstLineFrames(state, containingBlock->GetContent(),
                             containingBlock, frameItems);
     }
     else {
       // Use more complicated insert logic when inserting
       // XXXbz this method is a no-op, so it's easy for the args being passed
       // here to make no sense without anyone noticing...  If it ever stops
       // being a no-op, vet them carefully!
       InsertFirstLineFrames(state, container, containingBlock, &parentFrame,
                             prevSibling, frameItems);
     }
   }
   // We might have captions; put them into the caption list of the
   // outer table frame.
   if (captionItems.NotEmpty()) {
     NS_ASSERTION(nsGkAtoms::tableFrame == frameType ||
                  nsGkAtoms::tableOuterFrame == frameType,
                  "parent for caption is not table?");
     // We need to determine where to put the caption items; start with the
     // the parent frame that has already been determined and get the insertion
     // prevsibling of the first caption item.
     nsIFrame* captionParent = parentFrame;
     bool captionIsAppend;
     nsIFrame* captionPrevSibling = nullptr;
     // aIsRangeInsertSafe is ignored on purpose because it is irrelevant here.
     bool ignored;
     if (isSingleInsert) {
       captionPrevSibling =
         GetInsertionPrevSibling(captionParent, aContainer, aStartChild,
                                 &captionIsAppend, &ignored);
     } else {
       nsIContent* firstCaption = captionItems.FirstChild()->GetContent();
       // It is very important here that we skip the children in
       // [aStartChild,aEndChild) when looking for a
       // prevsibling.
       captionPrevSibling =
         GetInsertionPrevSibling(captionParent, aContainer, firstCaption,
                                 &captionIsAppend, &ignored,
                                 aStartChild, aEndChild);
     }
     nsIFrame* outerTable = nullptr;
     if (GetCaptionAdjustedParent(captionParent, captionItems.FirstChild(),
                                  &outerTable)) {
       // If the parent is not an outer table frame we will try to add frames
       // to a named child list that the parent does not honour and the frames
       // will get lost
       NS_ASSERTION(nsGkAtoms::tableOuterFrame == outerTable->GetType(),
                    "Pseudo frame construction failure; "
                    "a caption can be only a child of an outer table frame");
       // If the parent of our current prevSibling is different from the frame
       // we'll actually use as the parent, then the calculated insertion
       // point is now invalid (bug 341382).
       if (captionPrevSibling &&
           captionPrevSibling->GetParent() != outerTable) {
           captionPrevSibling = nullptr;
       }
       if (captionIsAppend) {
         AppendFrames(outerTable, nsIFrame::kCaptionList, captionItems);
       } else {
         InsertFrames(outerTable, nsIFrame::kCaptionList,
                      captionPrevSibling, captionItems);
       }
     }
   }
   if (frameItems.NotEmpty()) {
     // Notify the parent frame
     if (isAppend) {
       AppendFramesToParent(state, parentFrame, frameItems, prevSibling);
     } else {
       InsertFrames(parentFrame, kPrincipalList, prevSibling, frameItems);
     }
   }
   if (haveFirstLetterStyle) {
     // Recover the letter frames for the containing block when
     // it has first-letter style.
     RecoverLetterFrames(state.mFloatedItems.containingBlock);
   }
 #ifdef DEBUG
   if (gReallyNoisyContentUpdates && parentFrame) {
     printf("nsCSSFrameConstructor::ContentRangeInserted: resulting frame model:\n");
     parentFrame->List(stdout, 0);
   }
 #endif
 #ifdef ACCESSIBILITY
   nsAccessibilityService* accService = nsIPresShell::AccService();
   if (accService) {
     accService->ContentRangeInserted(mPresShell, aContainer,
                                      aStartChild, aEndChild);
   }
 #endif
   return NS_OK;
 }
 nsresult
 nsCSSFrameConstructor::ContentRemoved(nsIContent* aContainer,
                                       nsIContent* aChild,
                                       nsIContent* aOldNextSibling,
                                       RemoveFlags aFlags,
                                       bool*     aDidReconstruct)
 {
   AUTO_LAYOUT_PHASE_ENTRY_POINT(mPresShell->GetPresContext(), FrameC);
   NS_PRECONDITION(mUpdateCount != 0,
                   "Should be in an update while destroying frames");
   *aDidReconstruct = false;
   // XXXldb Do we need to re-resolve style to handle the CSS2 + combinator and
   // the :empty pseudo-class?
 #ifdef DEBUG
   if (gNoisyContentUpdates) {
     printf("nsCSSFrameConstructor::ContentRemoved container=%p child=%p "
            "old-next-sibling=%p\n",
            static_cast<void*>(aContainer),
            static_cast<void*>(aChild),
            static_cast<void*>(aOldNextSibling));
     if (gReallyNoisyContentUpdates) {
       aContainer->List(stdout, 0);
     }
   }
 #endif
   nsPresContext *presContext = mPresShell->GetPresContext();
   nsresult                  rv = NS_OK;
   // Find the child frame that maps the content
   nsIFrame* childFrame = aChild->GetPrimaryFrame();
   if (!childFrame || childFrame->GetContent() != aChild) {
     // XXXbz the GetContent() != aChild check is needed due to bug 135040.
     // Remove it once that's fixed.
     ClearUndisplayedContentIn(aChild, aContainer);
   }
 #ifdef MOZ_XUL
   if (NotifyListBoxBody(presContext, aContainer, aChild, aOldNextSibling,
                         mDocument, childFrame, CONTENT_REMOVED))
     return NS_OK;
 #endif // MOZ_XUL
   // If we're removing the root, then make sure to remove things starting at
   // the viewport's child instead of the primary frame (which might even be
   // null if the root had an XBL binding or display:none, even though the
   // frames above it got created).  We do the adjustment after the childFrame
   // check above, because we do want to clear any undisplayed content we might
   // have for the root.  Detecting removal of a root is a little exciting; in
   // particular, having a null aContainer is necessary but NOT sufficient.  Due
   // to how we process reframes, the content node might not even be in our
   // document by now.  So explicitly check whether the viewport's first kid's
   // content node is aChild.
   bool isRoot = false;
   if (!aContainer) {
     nsIFrame* viewport = GetRootFrame();
     if (viewport) {
       nsIFrame* firstChild = viewport->GetFirstPrincipalChild();
       if (firstChild && firstChild->GetContent() == aChild) {
         isRoot = true;
         childFrame = firstChild;
         NS_ASSERTION(!childFrame->GetNextSibling(), "How did that happen?");
       }
     }
   }
   if (aContainer && aContainer->HasFlag(NODE_IS_IN_SHADOW_TREE)) {
     // Recreate frames if content is removed from a ShadowRoot
     // because it may contain an insertion point which can change
     // how the host is rendered.
     nsIContent* bindingParent = aContainer->GetBindingParent();
     *aDidReconstruct = true;
     LAYOUT_PHASE_TEMP_EXIT();
     nsresult rv = RecreateFramesForContent(bindingParent, false);
     LAYOUT_PHASE_TEMP_REENTER();
     return rv;
   }
   if (childFrame) {
     InvalidateCanvasIfNeeded(mPresShell, aChild);
     // See whether we need to remove more than just childFrame
     LAYOUT_PHASE_TEMP_EXIT();
     if (MaybeRecreateContainerForFrameRemoval(childFrame, &rv)) {
       LAYOUT_PHASE_TEMP_REENTER();
       *aDidReconstruct = true;
       return rv;
     }
     LAYOUT_PHASE_TEMP_REENTER();
     // Get the childFrame's parent frame
     nsIFrame* parentFrame = childFrame->GetParent();
     nsIAtom* parentType = parentFrame->GetType();
     if (parentType == nsGkAtoms::frameSetFrame &&
         IsSpecialFramesetChild(aChild)) {
       // Just reframe the parent, since framesets are weird like that.
       *aDidReconstruct = true;
       LAYOUT_PHASE_TEMP_EXIT();
       nsresult rv = RecreateFramesForContent(parentFrame->GetContent(), false);
       LAYOUT_PHASE_TEMP_REENTER();
       return rv;
     }
     // If we're a child of MathML, then we should reframe the MathML content.
     // If we're non-MathML, then we would be wrapped in a block so we need to
     // check our grandparent in that case.
     nsIFrame* possibleMathMLAncestor = parentType == nsGkAtoms::blockFrame ?
          parentFrame->GetParent() : parentFrame;
     if (possibleMathMLAncestor->IsFrameOfType(nsIFrame::eMathML)) {
       *aDidReconstruct = true;
       LAYOUT_PHASE_TEMP_EXIT();
       nsresult rv = RecreateFramesForContent(possibleMathMLAncestor->GetContent(), false);
       LAYOUT_PHASE_TEMP_REENTER();
       return rv;
     }
     // Undo XUL wrapping if it's no longer needed.
     // (If we're in the XUL block-wrapping situation, parentFrame is the
     // wrapper frame.)
     nsIFrame* grandparentFrame = parentFrame->GetParent();
     if (grandparentFrame && grandparentFrame->IsBoxFrame() &&
         (grandparentFrame->GetStateBits() & NS_STATE_BOX_WRAPS_KIDS_IN_BLOCK) &&
         // check if this frame is the only one needing wrapping
         aChild == AnyKidsNeedBlockParent(parentFrame->GetFirstPrincipalChild()) &&
         !AnyKidsNeedBlockParent(childFrame->GetNextSibling())) {
       *aDidReconstruct = true;
       LAYOUT_PHASE_TEMP_EXIT();
       nsresult rv = RecreateFramesForContent(grandparentFrame->GetContent(), true);
       LAYOUT_PHASE_TEMP_REENTER();
       return rv;
     }
 #ifdef ACCESSIBILITY
     nsAccessibilityService* accService = nsIPresShell::AccService();
     if (accService) {
       accService->ContentRemoved(mPresShell, aContainer, aChild);
     }
 #endif
     // Examine the containing-block for the removed content and see if
     // :first-letter style applies.
     nsIFrame* inflowChild = childFrame;
     if (childFrame->GetStateBits() & NS_FRAME_OUT_OF_FLOW) {
       inflowChild = GetPlaceholderFrameFor(childFrame);
       NS_ASSERTION(inflowChild, "No placeholder for out-of-flow?");
     }
     nsIFrame* containingBlock =
       GetFloatContainingBlock(inflowChild->GetParent());
     bool haveFLS = containingBlock && HasFirstLetterStyle(containingBlock);
     if (haveFLS) {
       // Trap out to special routine that handles adjusting a blocks
       // frame tree when first-letter style is present.
 #ifdef NOISY_FIRST_LETTER
       printf("ContentRemoved: containingBlock=");
       nsFrame::ListTag(stdout, containingBlock);
       printf(" parentFrame=");
       nsFrame::ListTag(stdout, parentFrame);
       printf(" childFrame=");
       nsFrame::ListTag(stdout, childFrame);
       printf("\n");
 #endif
       // First update the containing blocks structure by removing the
       // existing letter frames. This makes the subsequent logic
       // simpler.
       RemoveLetterFrames(presContext, mPresShell, containingBlock);
       // Recover childFrame and parentFrame
       childFrame = aChild->GetPrimaryFrame();
       if (!childFrame || childFrame->GetContent() != aChild) {
         // XXXbz the GetContent() != aChild check is needed due to bug 135040.
         // Remove it once that's fixed.
         ClearUndisplayedContentIn(aChild, aContainer);
         return NS_OK;
       }
       parentFrame = childFrame->GetParent();
       parentType = parentFrame->GetType();
 #ifdef NOISY_FIRST_LETTER
       printf("  ==> revised parentFrame=");
       nsFrame::ListTag(stdout, parentFrame);
       printf(" childFrame=");
       nsFrame::ListTag(stdout, childFrame);
       printf("\n");
 #endif
     }
 #ifdef DEBUG
     if (gReallyNoisyContentUpdates) {
       printf("nsCSSFrameConstructor::ContentRemoved: childFrame=");
       nsFrame::ListTag(stdout, childFrame);
       putchar('\n');
       parentFrame->List(stdout, 0);
     }
 #endif
     // Notify the parent frame that it should delete the frame
     if (childFrame->GetStateBits() & NS_FRAME_OUT_OF_FLOW) {
       childFrame = GetPlaceholderFrameFor(childFrame);
       NS_ASSERTION(childFrame, "Missing placeholder frame for out of flow.");
       parentFrame = childFrame->GetParent();
     }
     rv = RemoveFrame(nsLayoutUtils::GetChildListNameFor(childFrame),
                      childFrame);
     //XXXfr NS_ENSURE_SUCCESS(rv, rv) ?
     if (isRoot) {
       mRootElementFrame = nullptr;
       mRootElementStyleFrame = nullptr;
       mDocElementContainingBlock = nullptr;
       mPageSequenceFrame = nullptr;
       mGfxScrollFrame = nullptr;
       mHasRootAbsPosContainingBlock = false;
       mFixedContainingBlock = GetRootFrame();
     }
     if (haveFLS && mRootElementFrame) {
       RecoverLetterFrames(containingBlock);
     }
     // If we're just reconstructing frames for the element, then the
     // following ContentInserted notification on the element will
     // take care of fixing up any adjacent text nodes.  We don't need
     // to do this if the table parent type of our parent type is not
     // eTypeBlock, though, because in that case the whitespace isn't
     // being suppressed due to us anyway.
     if (aContainer && !aChild->IsRootOfAnonymousSubtree() &&
         aFlags != REMOVE_FOR_RECONSTRUCTION &&
         GetParentType(parentType) == eTypeBlock) {
       // Adjacent whitespace-only text nodes might have been suppressed if
       // this node does not have inline ends. Create frames for them now
       // if necessary.
       // Reframe any text node just before the node being removed, if there is
       // one, and if it's not the last child or the first child. If a whitespace
       // textframe was being suppressed and it's now the last child or first
       // child then it can stay suppressed since the parent must be a block
       // and hence it's adjacent to a block end.
       // If aOldNextSibling is null, then the text node before the node being
       // removed is the last node, and we don't need to worry about it.
       if (aOldNextSibling) {
         nsIContent* prevSibling = aOldNextSibling->GetPreviousSibling();
         if (prevSibling && prevSibling->GetPreviousSibling()) {
           LAYOUT_PHASE_TEMP_EXIT();
           ReframeTextIfNeeded(aContainer, prevSibling);
           LAYOUT_PHASE_TEMP_REENTER();
         }
       }
       // Reframe any text node just after the node being removed, if there is
       // one, and if it's not the last child or the first child.
       if (aOldNextSibling && aOldNextSibling->GetNextSibling() &&
           aOldNextSibling->GetPreviousSibling()) {
         LAYOUT_PHASE_TEMP_EXIT();
         ReframeTextIfNeeded(aContainer, aOldNextSibling);
         LAYOUT_PHASE_TEMP_REENTER();
       }
     }
 #ifdef DEBUG
     if (gReallyNoisyContentUpdates && parentFrame) {
       printf("nsCSSFrameConstructor::ContentRemoved: resulting frame model:\n");
       parentFrame->List(stdout, 0);
     }
 #endif
   }
   return rv;
 }
 /**
  * This method invalidates the canvas when frames are removed or added for a
  * node that might have its background propagated to the canvas, i.e., a
  * document root node or an HTML BODY which is a child of the root node.
  *
  * @param aFrame a frame for a content node about to be removed or a frame that
  *               was just created for a content node that was inserted.
  */
 static void
 InvalidateCanvasIfNeeded(nsIPresShell* presShell, nsIContent* node)
 {
   NS_PRECONDITION(presShell->GetRootFrame(), "What happened here?");
   NS_PRECONDITION(presShell->GetPresContext(), "Say what?");
   //  Note that both in ContentRemoved and ContentInserted the content node
   //  will still have the right parent pointer, so looking at that is ok.
   nsIContent* parent = node->GetParent();
   if (parent) {
     // Has a parent; might not be what we want
     nsIContent* grandParent = parent->GetParent();
     if (grandParent) {
       // Has a grandparent, so not what we want
       return;
     }
     // Check whether it's an HTML body
     if (node->Tag() != nsGkAtoms::body ||
         !node->IsHTML()) {
       return;
     }
   }
   // At this point the node has no parent or it's an HTML <body> child of the
   // root.  We might not need to invalidate in this case (eg we might be in
   // XHTML or something), but chances are we want to.  Play it safe.
   // Invalidate the viewport.
   nsIFrame* rootFrame = presShell->GetRootFrame();
   rootFrame->InvalidateFrameSubtree();
 }
 nsIFrame*
 nsCSSFrameConstructor::EnsureFrameForTextNode(nsGenericDOMDataNode* aContent)
 {
   if (aContent->HasFlag(NS_CREATE_FRAME_IF_NON_WHITESPACE) &&
       !mAlwaysCreateFramesForIgnorableWhitespace) {
     // Text frame may have been suppressed. Disable suppression and signal
     // that a flush should be performed. We do this on a document-wide
     // basis so that pages that repeatedly query metrics for
     // collapsed-whitespace text nodes don't trigger pathological behavior.
     mAlwaysCreateFramesForIgnorableWhitespace = true;
     nsAutoScriptBlocker blocker;
     BeginUpdate();
     ReconstructDocElementHierarchy();
     EndUpdate();
   }
   return aContent->GetPrimaryFrame();
 }
 nsresult
 nsCSSFrameConstructor::CharacterDataChanged(nsIContent* aContent,
                                             CharacterDataChangeInfo* aInfo)
 {
   AUTO_LAYOUT_PHASE_ENTRY_POINT(mPresShell->GetPresContext(), FrameC);
   nsresult      rv = NS_OK;
   if ((aContent->HasFlag(NS_CREATE_FRAME_IF_NON_WHITESPACE) &&
        !aContent->TextIsOnlyWhitespace()) ||
       (aContent->HasFlag(NS_REFRAME_IF_WHITESPACE) &&
        aContent->TextIsOnlyWhitespace())) {
 #ifdef DEBUG
     nsIFrame* frame = aContent->GetPrimaryFrame();
     NS_ASSERTION(!frame || !frame->IsGeneratedContentFrame(),
                  "Bit should never be set on generated content");
 #endif
     LAYOUT_PHASE_TEMP_EXIT();
     nsresult rv = RecreateFramesForContent(aContent, false);
     LAYOUT_PHASE_TEMP_REENTER();
     return rv;
   }
   // Find the child frame
   nsIFrame* frame = aContent->GetPrimaryFrame();
   // Notify the first frame that maps the content. It will generate a reflow
   // command
   // It's possible the frame whose content changed isn't inserted into the
   // frame hierarchy yet, or that there is no frame that maps the content
   if (nullptr != frame) {
 #if 0
     NS_FRAME_LOG(NS_FRAME_TRACE_CALLS,
        ("nsCSSFrameConstructor::CharacterDataChanged: content=%p[%s] subcontent=%p frame=%p",
         aContent, ContentTag(aContent, 0),
         aSubContent, frame));
 #endif
     // Special check for text content that is a child of a letter frame.  If
     // this happens, we should remove the letter frame, do whatever we're
     // planning to do with this notification, then put the letter frame back.
     // Note that this is basically what RecreateFramesForContent ends up doing;
     // the reason we dont' want to call that here is that our text content
     // could be native anonymous, in which case RecreateFramesForContent would
     // completely barf on it.  And recreating the non-anonymous ancestor would
     // just lead us to come back into this notification (e.g. if quotes or
     // counters are involved), leading to a loop.
     nsIFrame* block = GetFloatContainingBlock(frame);
     bool haveFirstLetterStyle = false;
     if (block) {
       // See if the block has first-letter style applied to it.
       haveFirstLetterStyle = HasFirstLetterStyle(block);
       if (haveFirstLetterStyle) {
         RemoveLetterFrames(mPresShell->GetPresContext(), mPresShell,
                            block);
         // Reget |frame|, since we might have killed it.
         // Do we really need to call CharacterDataChanged in this case, though?
         frame = aContent->GetPrimaryFrame();
         NS_ASSERTION(frame, "Should have frame here!");
       }
     }
     frame->CharacterDataChanged(aInfo);
     if (haveFirstLetterStyle) {
       RecoverLetterFrames(block);
     }
   }
   return rv;
 }
 void
 nsCSSFrameConstructor::BeginUpdate() {
   NS_ASSERTION(!nsContentUtils::IsSafeToRunScript(),
                "Someone forgot a script blocker");
   nsRootPresContext* rootPresContext =
     mPresShell->GetPresContext()->GetRootPresContext();
   if (rootPresContext) {
     rootPresContext->IncrementDOMGeneration();
   }
   ++sGlobalGenerationNumber;
   ++mUpdateCount;
 }
 void
 nsCSSFrameConstructor::EndUpdate()
 {
   if (mUpdateCount == 1) {
     // This is the end of our last update.  Before we decrement
     // mUpdateCount, recalc quotes and counters as needed.
     RecalcQuotesAndCounters();
     NS_ASSERTION(mUpdateCount == 1, "Odd update count");
   }
   NS_ASSERTION(mUpdateCount, "Negative mUpdateCount!");
   --mUpdateCount;
 }
 void
 nsCSSFrameConstructor::RecalcQuotesAndCounters()
 {
   if (mQuotesDirty) {
     mQuotesDirty = false;
     mQuoteList.RecalcAll();
   }
   if (mCountersDirty) {
     mCountersDirty = false;
     mCounterManager.RecalcAll();
   }
   NS_ASSERTION(!mQuotesDirty, "Quotes updates will be lost");
   NS_ASSERTION(!mCountersDirty, "Counter updates will be lost");
 }
 void
 nsCSSFrameConstructor::WillDestroyFrameTree()
 {
 #if defined(DEBUG_dbaron_off)
   mCounterManager.Dump();
 #endif
   mIsDestroyingFrameTree = true;
   // Prevent frame tree destruction from being O(N^2)
   mQuoteList.Clear();
   mCounterManager.Clear();
   // Remove our presshell as a style flush observer.  But leave
   // RestyleManager::mObservingRefreshDriver true so we don't readd to
   // it even if someone tries to post restyle events on us from this
   // point on for some reason.
   mPresShell->GetPresContext()->RefreshDriver()->
     RemoveStyleFlushObserver(mPresShell);
   nsFrameManager::Destroy();
 }
 //STATIC
 // XXXbz I'd really like this method to go away. Once we have inline-block and
 // I can just use that for sized broken images, that can happen, maybe.
 void nsCSSFrameConstructor::GetAlternateTextFor(nsIContent*    aContent,
                                                 nsIAtom*       aTag,  // content object's tag
                                                 nsXPIDLString& aAltText)
 {
   // The "alt" attribute specifies alternate text that is rendered
   // when the image can not be displayed
   // If there's no "alt" attribute, and aContent is an input
   // element, then use the value of the "value" attribute
   if (!aContent->GetAttr(kNameSpaceID_None, nsGkAtoms::alt, aAltText) &&
       nsGkAtoms::input == aTag) {
     // If there's no "value" attribute either, then use the localized string
     // for "Submit" as the alternate text.
     if (!aContent->GetAttr(kNameSpaceID_None, nsGkAtoms::value, aAltText)) {
       nsContentUtils::GetLocalizedString(nsContentUtils::eFORMS_PROPERTIES,
                                          "Submit", aAltText);
     }
   }
 }
 nsIFrame*
 nsCSSFrameConstructor::CreateContinuingOuterTableFrame(nsIPresShell*    aPresShell,
                                                        nsPresContext*  aPresContext,
                                                        nsIFrame*        aFrame,
                                                        nsIFrame*        aParentFrame,
                                                        nsIContent*      aContent,
                                                        nsStyleContext*  aStyleContext)
 {
   nsIFrame* newFrame = NS_NewTableOuterFrame(aPresShell, aStyleContext);
   newFrame->Init(aContent, aParentFrame, aFrame);
   // Create a continuing inner table frame, and if there's a caption then
   // replicate the caption
   nsFrameItems  newChildFrames;
   nsIFrame* childFrame = aFrame->GetFirstPrincipalChild();
   if (childFrame) {
     nsIFrame* continuingTableFrame =
       CreateContinuingFrame(aPresContext, childFrame, newFrame);
     newChildFrames.AddChild(continuingTableFrame);
     NS_ASSERTION(!childFrame->GetNextSibling(),"there can be only one inner table frame");
   }
   // Set the outer table's initial child list
   newFrame->SetInitialChildList(kPrincipalList, newChildFrames);
   return newFrame;
 }
 nsIFrame*
 nsCSSFrameConstructor::CreateContinuingTableFrame(nsIPresShell* aPresShell,
                                                   nsPresContext*  aPresContext,
                                                   nsIFrame*        aFrame,
                                                   nsIFrame*        aParentFrame,
                                                   nsIContent*      aContent,
                                                   nsStyleContext*  aStyleContext)
 {
   nsIFrame* newFrame = NS_NewTableFrame(aPresShell, aStyleContext);
   newFrame->Init(aContent, aParentFrame, aFrame);
   // Replicate any header/footer frames
   nsFrameItems  childFrames;
   nsIFrame* childFrame = aFrame->GetFirstPrincipalChild();
   for ( ; childFrame; childFrame = childFrame->GetNextSibling()) {
     // See if it's a header/footer, possibly wrapped in a scroll frame.
     nsTableRowGroupFrame* rowGroupFrame =
       static_cast<nsTableRowGroupFrame*>(childFrame);
     // If the row group was continued, then don't replicate it.
     nsIFrame* rgNextInFlow = rowGroupFrame->GetNextInFlow();
     if (rgNextInFlow) {
       rowGroupFrame->SetRepeatable(false);
     }
     else if (rowGroupFrame->IsRepeatable()) {
       // Replicate the header/footer frame.
       nsTableRowGroupFrame*   headerFooterFrame;
       nsFrameItems            childItems;
       nsFrameConstructorState state(mPresShell,
                                     GetAbsoluteContainingBlock(newFrame, FIXED_POS),
                                     GetAbsoluteContainingBlock(newFrame, ABS_POS),
                                     nullptr);
       state.mCreatingExtraFrames = true;
       nsStyleContext* const headerFooterStyleContext = rowGroupFrame->StyleContext();
       headerFooterFrame = static_cast<nsTableRowGroupFrame*>
                                      (NS_NewTableRowGroupFrame(aPresShell, headerFooterStyleContext));
       nsIContent* headerFooter = rowGroupFrame->GetContent();
       headerFooterFrame->Init(headerFooter, newFrame, nullptr);
       nsFrameConstructorSaveState absoluteSaveState;
       MakeTablePartAbsoluteContainingBlockIfNeeded(state,
                                                    headerFooterStyleContext->StyleDisplay(),
                                                    absoluteSaveState,
                                                    headerFooterFrame);
       ProcessChildren(state, headerFooter, rowGroupFrame->StyleContext(),
                       headerFooterFrame, true, childItems, false,
                       nullptr);
       NS_ASSERTION(state.mFloatedItems.IsEmpty(), "unexpected floated element");
       headerFooterFrame->SetInitialChildList(kPrincipalList, childItems);
       headerFooterFrame->SetRepeatable(true);
       // Table specific initialization
       headerFooterFrame->InitRepeatedFrame(aPresContext, rowGroupFrame);
       // XXX Deal with absolute and fixed frames...
       childFrames.AddChild(headerFooterFrame);
     }
   }
   // Set the table frame's initial child list
   newFrame->SetInitialChildList(kPrincipalList, childFrames);
   return newFrame;
 }
 nsIFrame*
 nsCSSFrameConstructor::CreateContinuingFrame(nsPresContext* aPresContext,
                                              nsIFrame*       aFrame,
                                              nsIFrame*       aParentFrame,
                                              bool            aIsFluid)
 {
   nsIPresShell*              shell = aPresContext->PresShell();
   nsStyleContext*            styleContext = aFrame->StyleContext();
   nsIFrame*                  newFrame = nullptr;
   nsIFrame*                  nextContinuation = aFrame->GetNextContinuation();
   nsIFrame*                  nextInFlow = aFrame->GetNextInFlow();
   // Use the frame type to determine what type of frame to create
   nsIAtom* frameType = aFrame->GetType();
   nsIContent* content = aFrame->GetContent();
   NS_ASSERTION(aFrame->GetSplittableType() != NS_FRAME_NOT_SPLITTABLE,
                "why CreateContinuingFrame for a non-splittable frame?");
   if (nsGkAtoms::textFrame == frameType) {
     newFrame = NS_NewContinuingTextFrame(shell, styleContext);
     newFrame->Init(content, aParentFrame, aFrame);
   } else if (nsGkAtoms::inlineFrame == frameType) {
     newFrame = NS_NewInlineFrame(shell, styleContext);
     newFrame->Init(content, aParentFrame, aFrame);
   } else if (nsGkAtoms::blockFrame == frameType) {
     newFrame = NS_NewBlockFrame(shell, styleContext);
     newFrame->Init(content, aParentFrame, aFrame);
 #ifdef MOZ_XUL
   } else if (nsGkAtoms::XULLabelFrame == frameType) {
     newFrame = NS_NewXULLabelFrame(shell, styleContext);
     newFrame->Init(content, aParentFrame, aFrame);
 #endif
   } else if (nsGkAtoms::columnSetFrame == frameType) {
     newFrame = NS_NewColumnSetFrame(shell, styleContext, nsFrameState(0));
     newFrame->Init(content, aParentFrame, aFrame);
   } else if (nsGkAtoms::pageFrame == frameType) {
     nsIFrame* canvasFrame;
     newFrame = ConstructPageFrame(shell, aPresContext, aParentFrame, aFrame,
                                   canvasFrame);
   } else if (nsGkAtoms::tableOuterFrame == frameType) {
     newFrame =
       CreateContinuingOuterTableFrame(shell, aPresContext, aFrame, aParentFrame,
                                       content, styleContext);
   } else if (nsGkAtoms::tableFrame == frameType) {
     newFrame =
       CreateContinuingTableFrame(shell, aPresContext, aFrame, aParentFrame,
                                  content, styleContext);
   } else if (nsGkAtoms::tableRowGroupFrame == frameType) {
     newFrame = NS_NewTableRowGroupFrame(shell, styleContext);
     newFrame->Init(content, aParentFrame, aFrame);
     if (newFrame->GetStateBits() & NS_FRAME_CAN_HAVE_ABSPOS_CHILDREN) {
       nsTableFrame::RegisterPositionedTablePart(newFrame);
     }
   } else if (nsGkAtoms::tableRowFrame == frameType) {
     newFrame = NS_NewTableRowFrame(shell, styleContext);
     newFrame->Init(content, aParentFrame, aFrame);
     if (newFrame->GetStateBits() & NS_FRAME_CAN_HAVE_ABSPOS_CHILDREN) {
       nsTableFrame::RegisterPositionedTablePart(newFrame);
     }
     // Create a continuing frame for each table cell frame
     nsFrameItems  newChildList;
     nsIFrame* cellFrame = aFrame->GetFirstPrincipalChild();
     while (cellFrame) {
       // See if it's a table cell frame
       if (IS_TABLE_CELL(cellFrame->GetType())) {
         nsIFrame* continuingCellFrame =
           CreateContinuingFrame(aPresContext, cellFrame, newFrame);
         newChildList.AddChild(continuingCellFrame);
       }
       cellFrame = cellFrame->GetNextSibling();
     }
     // Set the table cell's initial child list
     newFrame->SetInitialChildList(kPrincipalList, newChildList);
   } else if (IS_TABLE_CELL(frameType)) {
     // Warning: If you change this and add a wrapper frame around table cell
     // frames, make sure Bug 368554 doesn't regress!
     // See IsInAutoWidthTableCellForQuirk() in nsImageFrame.cpp.
     newFrame = NS_NewTableCellFrame(shell, styleContext, IsBorderCollapse(aParentFrame));
     newFrame->Init(content, aParentFrame, aFrame);
     if (newFrame->GetStateBits() & NS_FRAME_CAN_HAVE_ABSPOS_CHILDREN) {
       nsTableFrame::RegisterPositionedTablePart(newFrame);
     }
     // Create a continuing area frame
     nsIFrame* blockFrame = aFrame->GetFirstPrincipalChild();
     nsIFrame* continuingBlockFrame =
       CreateContinuingFrame(aPresContext, blockFrame, newFrame);
     // Set the table cell's initial child list
     SetInitialSingleChild(newFrame, continuingBlockFrame);
   } else if (nsGkAtoms::lineFrame == frameType) {
     newFrame = NS_NewFirstLineFrame(shell, styleContext);
     newFrame->Init(content, aParentFrame, aFrame);
   } else if (nsGkAtoms::letterFrame == frameType) {
     newFrame = NS_NewFirstLetterFrame(shell, styleContext);
     newFrame->Init(content, aParentFrame, aFrame);
   } else if (nsGkAtoms::imageFrame == frameType) {
     newFrame = NS_NewImageFrame(shell, styleContext);
     newFrame->Init(content, aParentFrame, aFrame);
   } else if (nsGkAtoms::imageControlFrame == frameType) {
     newFrame = NS_NewImageControlFrame(shell, styleContext);
     newFrame->Init(content, aParentFrame, aFrame);
   } else if (nsGkAtoms::placeholderFrame == frameType) {
     // create a continuing out of flow frame
     nsIFrame* oofFrame = nsPlaceholderFrame::GetRealFrameForPlaceholder(aFrame);
     nsIFrame* oofContFrame =
       CreateContinuingFrame(aPresContext, oofFrame, aParentFrame);
     newFrame =
       CreatePlaceholderFrameFor(shell, content, oofContFrame, styleContext,
                                 aParentFrame, aFrame,
                                 aFrame->GetStateBits() & PLACEHOLDER_TYPE_MASK);
   } else if (nsGkAtoms::fieldSetFrame == frameType) {
     newFrame = NS_NewFieldSetFrame(shell, styleContext);
     newFrame->Init(content, aParentFrame, aFrame);
     // Create a continuing area frame
     // XXXbz we really shouldn't have to do this by hand!
     nsIFrame* blockFrame = GetFieldSetBlockFrame(aFrame);
     if (blockFrame) {
       nsIFrame* continuingBlockFrame =
         CreateContinuingFrame(aPresContext, blockFrame, newFrame);
       // Set the fieldset's initial child list
       SetInitialSingleChild(newFrame, continuingBlockFrame);
     } else {
       MOZ_ASSERT(aFrame->GetStateBits() & NS_FRAME_IS_OVERFLOW_CONTAINER,
                  "FieldSet block may only be null for overflow containers");
     }
   } else if (nsGkAtoms::legendFrame == frameType) {
     newFrame = NS_NewLegendFrame(shell, styleContext);
     newFrame->Init(content, aParentFrame, aFrame);
   } else if (nsGkAtoms::flexContainerFrame == frameType) {
     newFrame = NS_NewFlexContainerFrame(shell, styleContext);
     newFrame->Init(content, aParentFrame, aFrame);
   } else {
     NS_RUNTIMEABORT("unexpected frame type");
   }
   // Init() set newFrame to be a fluid continuation of aFrame.
   // If we want a non-fluid continuation, we need to call SetPrevContinuation()
   // to reset NS_FRAME_IS_FLUID_CONTINUATION.
   if (!aIsFluid) {
     newFrame->SetPrevContinuation(aFrame);
   }
   // A continuation of generated content is also generated content
   if (aFrame->GetStateBits() & NS_FRAME_GENERATED_CONTENT) {
     newFrame->AddStateBits(NS_FRAME_GENERATED_CONTENT);
   }
   // A continuation of nsIAnonymousContentCreator content is also
   // nsIAnonymousContentCreator created content
   if (aFrame->GetStateBits() & NS_FRAME_ANONYMOUSCONTENTCREATOR_CONTENT) {
     newFrame->AddStateBits(NS_FRAME_ANONYMOUSCONTENTCREATOR_CONTENT);
   }
   // A continuation of an out-of-flow is also an out-of-flow
   if (aFrame->GetStateBits() & NS_FRAME_OUT_OF_FLOW) {
     newFrame->AddStateBits(NS_FRAME_OUT_OF_FLOW);
   }
   if (nextInFlow) {
     nextInFlow->SetPrevInFlow(newFrame);
     newFrame->SetNextInFlow(nextInFlow);
   } else if (nextContinuation) {
     nextContinuation->SetPrevContinuation(newFrame);
     newFrame->SetNextContinuation(nextContinuation);
   }
   NS_POSTCONDITION(!newFrame->GetNextSibling(), "unexpected sibling");
   return newFrame;
 }
 nsresult
 nsCSSFrameConstructor::ReplicateFixedFrames(nsPageContentFrame* aParentFrame)
 {
   // Now deal with fixed-pos things....  They should appear on all pages,
   // so we want to move over the placeholders when processing the child
   // of the pageContentFrame.
   nsIFrame* prevPageContentFrame = aParentFrame->GetPrevInFlow();
   if (!prevPageContentFrame) {
     return NS_OK;
   }
   nsIFrame* canvasFrame = aParentFrame->GetFirstPrincipalChild();
   nsIFrame* prevCanvasFrame = prevPageContentFrame->GetFirstPrincipalChild();
   if (!canvasFrame || !prevCanvasFrame) {
     // document's root element frame missing
     return NS_ERROR_UNEXPECTED;
   }
   nsFrameItems fixedPlaceholders;
   nsIFrame* firstFixed = prevPageContentFrame->GetFirstChild(nsIFrame::kFixedList);
   if (!firstFixed) {
     return NS_OK;
   }
   // Don't allow abs-pos descendants of the fixed content to escape the content.
   // This should not normally be possible (because fixed-pos elements should
   // be absolute containers) but fixed-pos tables currently aren't abs-pos
   // containers.
   nsFrameConstructorState state(mPresShell, aParentFrame,
                                 nullptr,
                                 mRootElementFrame);
   state.mCreatingExtraFrames = true;
   // We can't use an ancestor filter here, because we're not going to
   // be usefully recurring down the tree.  This means that other
   // places in frame construction can't assume a filter is
   // initialized!
   // Iterate across fixed frames and replicate each whose placeholder is a
   // descendant of aFrame. (We don't want to explicitly copy placeholders that
   // are within fixed frames, because that would cause duplicates on the new
   // page - bug 389619)
   for (nsIFrame* fixed = firstFixed; fixed; fixed = fixed->GetNextSibling()) {
     nsIFrame* prevPlaceholder = GetPlaceholderFrameFor(fixed);
     if (prevPlaceholder &&
         nsLayoutUtils::IsProperAncestorFrame(prevCanvasFrame, prevPlaceholder)) {
       // We want to use the same style as the primary style frame for
       // our content
       nsIContent* content = fixed->GetContent();
       nsStyleContext* styleContext =
         nsLayoutUtils::GetStyleFrame(content)->StyleContext();
       FrameConstructionItemList items;
       AddFrameConstructionItemsInternal(state, content, canvasFrame,
                                         content->Tag(),
                                         content->GetNameSpaceID(),
                                         true,
                                         styleContext,
                                         ITEM_ALLOW_XBL_BASE |
                                           ITEM_ALLOW_PAGE_BREAK,
                                         nullptr, items);
       ConstructFramesFromItemList(state, items, canvasFrame, fixedPlaceholders);
     }
   }
   // Add the placeholders to our primary child list.
   // XXXbz this is a little screwed up, since the fixed frames will have
   // broken auto-positioning. Oh, well.
   NS_ASSERTION(!canvasFrame->GetFirstPrincipalChild(),
                "leaking frames; doc root continuation must be empty");
   canvasFrame->SetInitialChildList(kPrincipalList, fixedPlaceholders);
   return NS_OK;
 }
 nsIFrame*
 nsCSSFrameConstructor::GetInsertionPoint(nsIContent*   aContainer,
                                          nsIContent*   aChildContent,
                                          bool*         aMultiple)
 {
   nsBindingManager *bindingManager = mDocument->BindingManager();
   nsIContent* insertionElement;
   if (aChildContent) {
     // We've got an explicit insertion child. Check to see if it's
     // anonymous.
     if (aChildContent->GetBindingParent() == aContainer) {
       // This child content is anonymous. Don't use the insertion
       // point, since that's only for the explicit kids.
       return GetFrameFor(aContainer);
     }
     insertionElement = bindingManager->FindNestedInsertionPoint(aContainer, aChildContent);
   }
   else {
     bool multiple;
     insertionElement = bindingManager->FindNestedSingleInsertionPoint(aContainer, &multiple);
     if (multiple) {
       if (aMultiple) {
         *aMultiple = true;
       }
       return nullptr;
     }
   }
   if (!insertionElement) {
     insertionElement = aContainer;
   }
   nsIFrame* insertionPoint = GetFrameFor(insertionElement);
   // fieldsets have multiple insertion points.  Note that we might
   // have to look at insertionElement here...
   if (aMultiple && insertionElement->IsHTML(nsGkAtoms::fieldset)) {
     *aMultiple = true;
   }
   return insertionPoint;
 }
 // Capture state for the frame tree rooted at the frame associated with the
 // content object, aContent
 void
 nsCSSFrameConstructor::CaptureStateForFramesOf(nsIContent* aContent,
                                                nsILayoutHistoryState* aHistoryState)
 {
   if (!aHistoryState) {
     return;
   }
   nsIFrame* frame = aContent->GetPrimaryFrame();
   if (frame == mRootElementFrame) {
     frame = mFixedContainingBlock;
   }
   for ( ; frame;
         frame = nsLayoutUtils::GetNextContinuationOrIBSplitSibling(frame)) {
     CaptureFrameState(frame, aHistoryState);
   }
 }
 static bool EqualURIs(mozilla::css::URLValue *aURI1,
                       mozilla::css::URLValue *aURI2)
 {
   return aURI1 == aURI2 ||    // handle null==null, and optimize
          (aURI1 && aURI2 && aURI1->URIEquals(*aURI2));
 }
 nsresult
 nsCSSFrameConstructor::MaybeRecreateFramesForElement(Element* aElement)
 {
   nsRefPtr<nsStyleContext> oldContext = GetUndisplayedContent(aElement);
   if (!oldContext) {
     return NS_OK;
   }
   // The parent has a frame, so try resolving a new context.
   nsRefPtr<nsStyleContext> newContext = mPresShell->StyleSet()->
     ResolveStyleFor(aElement, oldContext->GetParent());
   ChangeUndisplayedContent(aElement, newContext);
   const nsStyleDisplay* disp = newContext->StyleDisplay();
   if (disp->mDisplay == NS_STYLE_DISPLAY_NONE) {
     // We can skip trying to recreate frames here, but only if our style
     // context does not have a binding URI that differs from our old one.
     // Otherwise, we should try to recreate, because we may want to apply the
     // new binding
     if (!disp->mBinding) {
       return NS_OK;
     }
     const nsStyleDisplay* oldDisp = oldContext->PeekStyleDisplay();
     if (oldDisp && EqualURIs(disp->mBinding, oldDisp->mBinding)) {
       return NS_OK;
     }
   }
   return RecreateFramesForContent(aElement, false);
 }
 static nsIFrame*
 FindFirstNonWhitespaceChild(nsIFrame* aParentFrame)
 {
   nsIFrame* f = aParentFrame->GetFirstPrincipalChild();
   while (f && f->GetType() == nsGkAtoms::textFrame &&
          f->GetContent()->TextIsOnlyWhitespace()) {
     f = f->GetNextSibling();
   }
   return f;
 }
 static nsIFrame*
 FindNextNonWhitespaceSibling(nsIFrame* aFrame)
 {
   nsIFrame* f = aFrame;
   do {
     f = f->GetNextSibling();
   } while (f && f->GetType() == nsGkAtoms::textFrame &&
            f->GetContent()->TextIsOnlyWhitespace());
   return f;
 }
 static nsIFrame*
 FindPreviousNonWhitespaceSibling(nsIFrame* aFrame)
 {
   nsIFrame* f = aFrame;
   do {
     f = f->GetPrevSibling();
   } while (f && f->GetType() == nsGkAtoms::textFrame &&
            f->GetContent()->TextIsOnlyWhitespace());
   return f;
 }
 bool
 nsCSSFrameConstructor::MaybeRecreateContainerForFrameRemoval(nsIFrame* aFrame,
                                                              nsresult* aResult)
 {
   NS_PRECONDITION(aFrame, "Must have a frame");
   NS_PRECONDITION(aFrame->GetParent(), "Frame shouldn't be root");
   NS_PRECONDITION(aResult, "Null out param?");
   NS_PRECONDITION(aFrame == aFrame->FirstContinuation(),
                   "aFrame not the result of GetPrimaryFrame()?");
   if (IsFramePartOfIBSplit(aFrame)) {
     // The removal functions can't handle removal of an {ib} split directly; we
     // need to rebuild the containing block.
 #ifdef DEBUG
     if (gNoisyContentUpdates) {
       printf("nsCSSFrameConstructor::MaybeRecreateContainerForFrameRemoval: "
              "frame=");
       nsFrame::ListTag(stdout, aFrame);
       printf(" is ib-split\n");
     }
 #endif
     *aResult = ReframeContainingBlock(aFrame);
     return true;
   }
   if (aFrame->GetContentInsertionFrame()->GetType() == nsGkAtoms::legendFrame &&
       aFrame->GetParent()->GetType() == nsGkAtoms::fieldSetFrame) {
     // When we remove the legend for a fieldset, we should reframe
     // the fieldset to ensure another legend is used, if there is one
     *aResult = RecreateFramesForContent(aFrame->GetParent()->GetContent(), false);
     return true;
   }
   // Now check for possibly needing to reconstruct due to a pseudo parent
   nsIFrame* inFlowFrame =
     (aFrame->GetStateBits() & NS_FRAME_OUT_OF_FLOW) ?
       GetPlaceholderFrameFor(aFrame) : aFrame;
   MOZ_ASSERT(inFlowFrame, "How did that happen?");
   MOZ_ASSERT(inFlowFrame == inFlowFrame->FirstContinuation(),
              "placeholder for primary frame has previous continuations?");
   nsIFrame* parent = inFlowFrame->GetParent();
   if (IsTablePseudo(parent)) {
     if (FindFirstNonWhitespaceChild(parent) == inFlowFrame ||
         !FindNextNonWhitespaceSibling(inFlowFrame->LastContinuation()) ||
         // If we're a table-column-group, then the GetFirstChild check above is
         // not going to catch cases when we're the first child.
         (inFlowFrame->GetType() == nsGkAtoms::tableColGroupFrame &&
          parent->GetFirstChild(nsIFrame::kColGroupList) == inFlowFrame) ||
         // Similar if we're a table-caption.
         (inFlowFrame->GetType() == nsGkAtoms::tableCaptionFrame &&
          parent->GetFirstChild(nsIFrame::kCaptionList) == inFlowFrame)) {
       // We're the first or last frame in the pseudo.  Need to reframe.
       // Good enough to recreate frames for |parent|'s content
       *aResult = RecreateFramesForContent(parent->GetContent(), true);
       return true;
     }
   }
   // Might need to reconstruct things if this frame's nextSibling is a table
   // pseudo, since removal of this frame might mean that this pseudo needs to
   // get merged with the frame's prevSibling if that's also a table pseudo.
   nsIFrame* nextSibling =
     FindNextNonWhitespaceSibling(inFlowFrame->LastContinuation());
   NS_ASSERTION(!IsTablePseudo(inFlowFrame), "Shouldn't happen here");
   if (nextSibling && IsTablePseudo(nextSibling)) {
     nsIFrame* prevSibling = FindPreviousNonWhitespaceSibling(inFlowFrame);
     if (prevSibling && IsTablePseudo(prevSibling)) {
 #ifdef DEBUG
       if (gNoisyContentUpdates) {
         printf("nsCSSFrameConstructor::MaybeRecreateContainerForFrameRemoval: "
                  "frame=");
         nsFrame::ListTag(stdout, aFrame);
         printf(" has a table pseudo next sibling of different type and a "
                  "table pseudo prevsibling\n");
       }
 #endif
       // Good enough to recreate frames for aFrame's parent's content; even if
       // aFrame's parent is a table pseudo, that'll be the right content node.
       *aResult = RecreateFramesForContent(parent->GetContent(), true);
       return true;
     }
   }
   // Might need to reconstruct things if the removed frame's nextSibling is an
   // anonymous flex item.  The removed frame might've been what divided two
   // runs of inline content into two anonymous flex items, which would now
   // need to be merged.
   // NOTE: It's fine that we've advanced nextSibling past whitespace (up above);
   // we're only interested in anonymous flex items here, and those can never
   // be adjacent to whitespace, since they absorb contiguous runs of inline
   // non-replaced content (including whitespace).
   if (nextSibling && IsAnonymousFlexItem(nextSibling)) {
     NS_ABORT_IF_FALSE(parent->GetType() == nsGkAtoms::flexContainerFrame,
                       "anonymous flex items should only exist as children "
                       "of flex container frames");
 #ifdef DEBUG
     if (gNoisyContentUpdates) {
       printf("nsCSSFrameConstructor::MaybeRecreateContainerForFrameRemoval: "
              "frame=");
       nsFrame::ListTag(stdout, aFrame);
       printf(" has an anonymous flex item as its next sibling\n");
     }
 #endif // DEBUG
     // Recreate frames for the flex container (the removed frame's parent)
     *aResult = RecreateFramesForContent(parent->GetContent(), true);
     return true;
   }
   // Might need to reconstruct things if the removed frame's nextSibling is
   // null and its parent is an anonymous flex item. (This might be the last
   // remaining child of that anonymous flex item, which can then go away.)
   if (!nextSibling && IsAnonymousFlexItem(parent)) {
     NS_ABORT_IF_FALSE(parent->GetParent() &&
                       parent->GetParent()->GetType() == nsGkAtoms::flexContainerFrame,
                       "anonymous flex items should only exist as children "
                       "of flex container frames");
 #ifdef DEBUG
     if (gNoisyContentUpdates) {
       printf("nsCSSFrameConstructor::MaybeRecreateContainerForFrameRemoval: "
              "frame=");
       nsFrame::ListTag(stdout, aFrame);
       printf(" has an anonymous flex item as its parent\n");
     }
 #endif // DEBUG
     // Recreate frames for the flex container (the removed frame's grandparent)
     *aResult = RecreateFramesForContent(parent->GetParent()->GetContent(),
                                         true);
     return true;
   }
 #ifdef MOZ_XUL
   if (aFrame->GetType() == nsGkAtoms::popupSetFrame) {
     nsIRootBox* rootBox = nsIRootBox::GetRootBox(mPresShell);
     if (rootBox && rootBox->GetPopupSetFrame() == aFrame) {
       *aResult = ReconstructDocElementHierarchy();
       return true;
     }
   }
 #endif
   // Reconstruct if inflowFrame is parent's only child, and parent is, or has,
   // a non-fluid continuation, i.e. it was split by bidi resolution
   if (!inFlowFrame->GetPrevSibling() &&
       !inFlowFrame->GetNextSibling() &&
       ((parent->GetPrevContinuation() && !parent->GetPrevInFlow()) ||
        (parent->GetNextContinuation() && !parent->GetNextInFlow()))) {
     *aResult = RecreateFramesForContent(parent->GetContent(), true);
     return true;
   }
   // We might still need to reconstruct things if the parent of inFlowFrame is
   // ib-split, since in that case the removal of aFrame might affect the
   // splitting of its parent.
   if (!IsFramePartOfIBSplit(parent)) {
     return false;
   }
   // If inFlowFrame is not the only in-flow child of |parent|, then removing
   // it will change nothing about the {ib} split.
   if (inFlowFrame != parent->GetFirstPrincipalChild() ||
       inFlowFrame->LastContinuation()->GetNextSibling()) {
     return false;
   }
   // If the parent is the first or last part of the {ib} split, then
   // removing one of its kids will have no effect on the splitting.
   // Get the first continuation up front so we don't have to do it twice.
   nsIFrame* parentFirstContinuation = parent->FirstContinuation();
   if (!GetIBSplitSibling(parentFirstContinuation) ||
       !GetIBSplitPrevSibling(parentFirstContinuation)) {
     return false;
   }
 #ifdef DEBUG
   if (gNoisyContentUpdates) {
     printf("nsCSSFrameConstructor::MaybeRecreateContainerForFrameRemoval: "
            "frame=");
     nsFrame::ListTag(stdout, parent);
     printf(" is ib-split\n");
   }
 #endif
   *aResult = ReframeContainingBlock(parent);
   return true;
 }
 nsresult
 nsCSSFrameConstructor::RecreateFramesForContent(nsIContent* aContent,
                                                 bool aAsyncInsert)
 {
   NS_PRECONDITION(!aAsyncInsert || aContent->IsElement(),
                   "Can only insert elements async");
   // If there is no document, we don't want to recreate frames for it.  (You
   // shouldn't generally be giving this method content without a document
   // anyway).
   // Rebuilding the frame tree can have bad effects, especially if it's the
   // frame tree for chrome (see bug 157322).
   NS_ENSURE_TRUE(aContent->GetDocument(), NS_ERROR_FAILURE);
   // Is the frame ib-split? If so, we need to reframe the containing
   // block *here*, rather than trying to remove and re-insert the
   // content (which would otherwise result in *two* nested reframe
   // containing block from ContentRemoved() and ContentInserted(),
   // below!).  We'd really like to optimize away one of those
   // containing block reframes, hence the code here.
   nsIFrame* frame = aContent->GetPrimaryFrame();
   if (frame && frame->IsFrameOfType(nsIFrame::eMathML)) {
     // Reframe the topmost MathML element to prevent exponential blowup
     // (see bug 397518)
     while (true) {
       nsIContent* parentContent = aContent->GetParent();
       nsIFrame* parentContentFrame = parentContent->GetPrimaryFrame();
       if (!parentContentFrame || !parentContentFrame->IsFrameOfType(nsIFrame::eMathML))
         break;
       aContent = parentContent;
       frame = parentContentFrame;
     }
   }
   if (frame) {
     nsIFrame* nonGeneratedAncestor = nsLayoutUtils::GetNonGeneratedAncestor(frame);
     if (nonGeneratedAncestor->GetContent() != aContent) {
       return RecreateFramesForContent(nonGeneratedAncestor->GetContent(), aAsyncInsert);
     }
     if (frame->GetStateBits() & NS_FRAME_ANONYMOUSCONTENTCREATOR_CONTENT) {
       // Recreate the frames for the entire nsIAnonymousContentCreator tree
       // since |frame| or one of its descendants may need an nsStyleContext
       // that associates it to a CSS pseudo-element, and only the
       // nsIAnonymousContentCreator that created this content knows how to make
       // that happen.
       nsIAnonymousContentCreator* acc = nullptr;
       nsIFrame* ancestor = frame->GetParent();
       while (!(acc = do_QueryFrame(ancestor))) {
         ancestor = ancestor->GetParent();
       }
       NS_ASSERTION(acc, "Where is the nsIAnonymousContentCreator? We may fail "
                         "to recreate its content correctly");
       // nsSVGUseFrame is special, and we know this is unnecessary for it.
       if (ancestor->GetType() != nsGkAtoms::svgUseFrame) {
         NS_ASSERTION(aContent->IsInNativeAnonymousSubtree(),
                      "Why is NS_FRAME_ANONYMOUSCONTENTCREATOR_CONTENT set?");
         return RecreateFramesForContent(ancestor->GetContent(), aAsyncInsert);
       }
     }
     nsIFrame* parent = frame->GetParent();
     nsIContent* parentContent = parent ? parent->GetContent() : nullptr;
     // If the parent frame is a leaf then the subsequent insert will fail to
     // create a frame, so we need to recreate the parent content. This happens
     // with native anonymous content from the editor.
     if (parent && parent->IsLeaf() && parentContent &&
         parentContent != aContent) {
       return RecreateFramesForContent(parentContent, aAsyncInsert);
     }
   }
   nsresult rv = NS_OK;
   if (frame && MaybeRecreateContainerForFrameRemoval(frame, &rv)) {
     return rv;
   }
   nsINode* containerNode = aContent->GetParentNode();
   // XXXbz how can containerNode be null here?
   if (containerNode) {
     // Before removing the frames associated with the content object,
     // ask them to save their state onto a temporary state object.
     CaptureStateForFramesOf(aContent, mTempFrameTreeState);
     // Need the nsIContent parent, which might be null here, since we need to
     // pass it to ContentInserted and ContentRemoved.
     nsCOMPtr<nsIContent> container = aContent->GetParent();
     // Remove the frames associated with the content object.
     bool didReconstruct;
     rv = ContentRemoved(container, aContent,
                         aContent->IsRootOfAnonymousSubtree() ?
                           nullptr :
                           aContent->GetNextSibling(),
                         REMOVE_FOR_RECONSTRUCTION, &didReconstruct);
     if (NS_SUCCEEDED(rv) && !didReconstruct) {
       // Now, recreate the frames associated with this content object. If
       // ContentRemoved triggered reconstruction, then we don't need to do this
       // because the frames will already have been built.
       if (aAsyncInsert) {
         RestyleManager()->PostRestyleEvent(
           aContent->AsElement(), nsRestyleHint(0), nsChangeHint_ReconstructFrame);
       } else {
         rv = ContentInserted(container, aContent, mTempFrameTreeState, false);
       }
     }
   }
   return rv;
 }
 //////////////////////////////////////////////////////////////////////
 // Block frame construction code
 already_AddRefed<nsStyleContext>
 nsCSSFrameConstructor::GetFirstLetterStyle(nsIContent* aContent,
                                            nsStyleContext* aStyleContext)
 {
   if (aContent) {
     return mPresShell->StyleSet()->
       ResolvePseudoElementStyle(aContent->AsElement(),
                                 nsCSSPseudoElements::ePseudo_firstLetter,
                                 aStyleContext,
                                 nullptr);
   }
   return nullptr;
 }
 already_AddRefed<nsStyleContext>
 nsCSSFrameConstructor::GetFirstLineStyle(nsIContent* aContent,
                                          nsStyleContext* aStyleContext)
 {
   if (aContent) {
     return mPresShell->StyleSet()->
       ResolvePseudoElementStyle(aContent->AsElement(),
                                 nsCSSPseudoElements::ePseudo_firstLine,
                                 aStyleContext,
                                 nullptr);
   }
   return nullptr;
 }
 // Predicate to see if a given content (block element) has
 // first-letter style applied to it.
 bool
 nsCSSFrameConstructor::ShouldHaveFirstLetterStyle(nsIContent* aContent,
                                                   nsStyleContext* aStyleContext)
 {
   return nsLayoutUtils::HasPseudoStyle(aContent, aStyleContext,
                                        nsCSSPseudoElements::ePseudo_firstLetter,
                                        mPresShell->GetPresContext());
 }
 bool
 nsCSSFrameConstructor::HasFirstLetterStyle(nsIFrame* aBlockFrame)
 {
   NS_PRECONDITION(aBlockFrame, "Need a frame");
   NS_ASSERTION(nsLayoutUtils::GetAsBlock(aBlockFrame),
                "Not a block frame?");
   return (aBlockFrame->GetStateBits() & NS_BLOCK_HAS_FIRST_LETTER_STYLE) != 0;
 }
 bool
 nsCSSFrameConstructor::ShouldHaveFirstLineStyle(nsIContent* aContent,
                                                 nsStyleContext* aStyleContext)
 {
   bool hasFirstLine =
     nsLayoutUtils::HasPseudoStyle(aContent, aStyleContext,
                                   nsCSSPseudoElements::ePseudo_firstLine,
                                   mPresShell->GetPresContext());
   if (hasFirstLine) {
     // But disable for fieldsets
     int32_t namespaceID;
     nsIAtom* tag = mDocument->BindingManager()->ResolveTag(aContent,
                                                            &namespaceID);
     // This check must match the one in FindHTMLData.
     hasFirstLine = tag != nsGkAtoms::fieldset ||
       namespaceID != kNameSpaceID_XHTML;
   }
   return hasFirstLine;
 }
 void
 nsCSSFrameConstructor::ShouldHaveSpecialBlockStyle(nsIContent* aContent,
                                                    nsStyleContext* aStyleContext,
                                                    bool* aHaveFirstLetterStyle,
                                                    bool* aHaveFirstLineStyle)
 {
   *aHaveFirstLetterStyle =
     ShouldHaveFirstLetterStyle(aContent, aStyleContext);
   *aHaveFirstLineStyle =
     ShouldHaveFirstLineStyle(aContent, aStyleContext);
 }
 /* static */
 const nsCSSFrameConstructor::PseudoParentData
 nsCSSFrameConstructor::sPseudoParentData[eParentTypeCount] = {
   { // Cell
     FULL_CTOR_FCDATA(FCDATA_IS_TABLE_PART | FCDATA_SKIP_FRAMESET |
                      FCDATA_USE_CHILD_ITEMS |
                      FCDATA_DESIRED_PARENT_TYPE_TO_BITS(eTypeRow),
                      &nsCSSFrameConstructor::ConstructTableCell),
     &nsCSSAnonBoxes::tableCell
   },
   { // Row
     FULL_CTOR_FCDATA(FCDATA_IS_TABLE_PART | FCDATA_SKIP_FRAMESET |
                      FCDATA_USE_CHILD_ITEMS |
                      FCDATA_DESIRED_PARENT_TYPE_TO_BITS(eTypeRowGroup),
                      &nsCSSFrameConstructor::ConstructTableRowOrRowGroup),
     &nsCSSAnonBoxes::tableRow
   },
   { // Row group
     FULL_CTOR_FCDATA(FCDATA_IS_TABLE_PART | FCDATA_SKIP_FRAMESET |
                      FCDATA_USE_CHILD_ITEMS |
                      FCDATA_DESIRED_PARENT_TYPE_TO_BITS(eTypeTable),
                      &nsCSSFrameConstructor::ConstructTableRowOrRowGroup),
     &nsCSSAnonBoxes::tableRowGroup
   },
   { // Column group
     FCDATA_DECL(FCDATA_IS_TABLE_PART | FCDATA_SKIP_FRAMESET |
                 FCDATA_DISALLOW_OUT_OF_FLOW | FCDATA_USE_CHILD_ITEMS |
                 FCDATA_SKIP_ABSPOS_PUSH |
                 FCDATA_DESIRED_PARENT_TYPE_TO_BITS(eTypeTable),
                 NS_NewTableColGroupFrame),
     &nsCSSAnonBoxes::tableColGroup
   },
   { // Table
     FULL_CTOR_FCDATA(FCDATA_SKIP_FRAMESET | FCDATA_USE_CHILD_ITEMS,
                      &nsCSSFrameConstructor::ConstructTable),
     &nsCSSAnonBoxes::table
   }
 };
 void
 nsCSSFrameConstructor::CreateNeededAnonFlexItems(
   nsFrameConstructorState& aState,
   FrameConstructionItemList& aItems,
   nsIFrame* aParentFrame)
 {
   if (aItems.IsEmpty() ||
       aParentFrame->GetType() != nsGkAtoms::flexContainerFrame) {
     return;
   }
   FCItemIterator iter(aItems);
   do {
     // Advance iter past children that don't want to be wrapped
     if (iter.SkipItemsThatDontNeedAnonFlexItem(aState)) {
       // Hit the end of the items without finding any remaining children that
       // need to be wrapped. We're finished!
       return;
     }
     // If our next potentially-wrappable child is whitespace, then see if
     // there's anything wrappable immediately after it. If not, we just drop
     // the whitespace and move on. (We're not supposed to create any anonymous
     // flex items that _only_ contain whitespace).
     // (BUT if this is generated content, then we don't give whitespace nodes
     // any special treatment, because they're probably not really whitespace --
     // they're just temporarily empty, waiting for their generated text.)
     // XXXdholbert If this node's generated text will *actually end up being
     // entirely whitespace*, then we technically should still skip over it, per
     // the flexbox spec. I'm not bothering with that at this point, since it's
     // a pretty extreme edge case.
     if (!aParentFrame->IsGeneratedContentFrame() &&
         iter.item().IsWhitespace(aState)) {
       FCItemIterator afterWhitespaceIter(iter);
       bool hitEnd = afterWhitespaceIter.SkipWhitespace(aState);
       bool nextChildNeedsAnonFlexItem =
         !hitEnd && afterWhitespaceIter.item().NeedsAnonFlexItem(aState);
       if (!nextChildNeedsAnonFlexItem) {
         // There's nothing after the whitespace that we need to wrap, so we
         // just drop this run of whitespace.
         iter.DeleteItemsTo(afterWhitespaceIter);
         if (hitEnd) {
           // Nothing left to do -- we're finished!
           return;
         }
         // else, we have a next child and it does not want to be wrapped.  So,
         // we jump back to the beginning of the loop to skip over that child
         // (and anything else non-wrappable after it)
         NS_ABORT_IF_FALSE(!iter.IsDone() &&
                           !iter.item().NeedsAnonFlexItem(aState),
                           "hitEnd and/or nextChildNeedsAnonFlexItem lied");
         continue;
       }
     }
     // Now |iter| points to the first child that needs to be wrapped in an
     // anonymous flex item. Now we see how many children after it also want
     // to be wrapped in an anonymous flex item.
     FCItemIterator endIter(iter); // iterator to find the end of the group
     endIter.SkipItemsThatNeedAnonFlexItem(aState);
     NS_ASSERTION(iter != endIter,
                  "Should've had at least one wrappable child to seek past");
     // Now, we create the anonymous flex item to contain the children
     // between |iter| and |endIter|.
     nsIAtom* pseudoType = nsCSSAnonBoxes::anonymousFlexItem;
     nsStyleContext* parentStyle = aParentFrame->StyleContext();
     nsIContent* parentContent = aParentFrame->GetContent();
     already_AddRefed<nsStyleContext> wrapperStyle =
       mPresShell->StyleSet()->ResolveAnonymousBoxStyle(pseudoType, parentStyle);
     static const FrameConstructionData sBlockFormattingContextFCData =
       FCDATA_DECL(FCDATA_SKIP_FRAMESET | FCDATA_USE_CHILD_ITEMS,
                   NS_NewBlockFormattingContext);
     FrameConstructionItem* newItem =
       new FrameConstructionItem(&sBlockFormattingContextFCData,
                                 // Use the content of our parent frame
                                 parentContent,
                                 // Lie about the tag; it doesn't matter anyway
                                 pseudoType,
                                 iter.item().mNameSpaceID,
                                 // no pending binding
                                 nullptr,
                                 wrapperStyle,
                                 true, nullptr);
     newItem->mIsAllInline = newItem->mHasInlineEnds =
       newItem->mStyleContext->StyleDisplay()->IsInlineOutsideStyle();
     newItem->mIsBlock = !newItem->mIsAllInline;
     NS_ABORT_IF_FALSE(!newItem->mIsAllInline && newItem->mIsBlock,
                       "expecting anonymous flex items to be block-level "
                       "(this will make a difference when we encounter "
                       "'flex-align: baseline')");
     // Anonymous flex items induce line boundaries around their
     // contents.
     newItem->mChildItems.SetLineBoundaryAtStart(true);
     newItem->mChildItems.SetLineBoundaryAtEnd(true);
     // The parent of the items in aItems is also the parent of the items
     // in mChildItems
     newItem->mChildItems.SetParentHasNoXBLChildren(
       aItems.ParentHasNoXBLChildren());
     // Eat up all items between |iter| and |endIter| and put them in our
     // wrapper. This advances |iter| to point to |endIter|.
     iter.AppendItemsToList(endIter, newItem->mChildItems);
     iter.InsertItem(newItem);
   } while (!iter.IsDone());
 }
 /*
  * This function works as follows: we walk through the child list (aItems) and
  * find items that cannot have aParentFrame as their parent.  We wrap
  * continuous runs of such items into a FrameConstructionItem for a frame that
  * gets them closer to their desired parents.  For example, a run of non-row
  * children of a row-group will get wrapped in a row.  When we later construct
  * the frame for this wrapper (in this case for the row), it'll be the correct
  * parent for the cells in the set of items we wrapped or we'll wrap cells
  * around everything else.  At the end of this method, aItems is guaranteed to
  * contain only items for frames that can be direct kids of aParentFrame.
  */
 void
 nsCSSFrameConstructor::CreateNeededTablePseudos(nsFrameConstructorState& aState,
                                                 FrameConstructionItemList& aItems,
                                                 nsIFrame* aParentFrame)
 {
   ParentType ourParentType = GetParentType(aParentFrame);
   if (aItems.AllWantParentType(ourParentType)) {
     // Nothing to do here
     return;
   }
   FCItemIterator iter(aItems);
   do {
     if (iter.SkipItemsWantingParentType(ourParentType)) {
       // Nothing else to do here; we're finished
       return;
     }
     // Now we're pointing to the first child that wants a different parent
     // type.
     // Now try to figure out what kids we can group together.  We can generally
     // group everything that has a different desired parent type from us.  Two
     // exceptions to this:
     // 1) If our parent type is table, we can't group columns with anything
     //    else other than whitespace.
     // 2) Whitespace that lies between two things we can group which both want
     //    a non-block parent should be dropped, even if we can't group them
     //    with each other and even if the whitespace wants a parent of
     //    ourParentType.  Ends of the list count as things that don't want a
     //    block parent (so that for example we'll drop a whitespace-only list).
     FCItemIterator endIter(iter); /* iterator to find the end of the group */
     ParentType groupingParentType = endIter.item().DesiredParentType();
     if (aItems.AllWantParentType(groupingParentType) &&
         groupingParentType != eTypeBlock) {
       // Just group them all and be done with it.  We need the check for
       // eTypeBlock here to catch the "all the items are whitespace" case
       // described above.
       endIter.SetToEnd();
     } else {
       // Locate the end of the group.
       // Keep track of the type the previous item wanted, in case we have to
       // deal with whitespace.  Start it off with ourParentType, since that's
       // the last thing |iter| would have skipped over.
       ParentType prevParentType = ourParentType;
       do {
         /* Walk an iterator past any whitespace that we might be able to drop from the list */
         FCItemIterator spaceEndIter(endIter);
         if (prevParentType != eTypeBlock &&
             !aParentFrame->IsGeneratedContentFrame() &&
             spaceEndIter.item().IsWhitespace(aState)) {
           bool trailingSpaces = spaceEndIter.SkipWhitespace(aState);
           // We drop the whitespace if these are not trailing spaces and the next item
           // does not want a block parent (see case 2 above)
           // if these are trailing spaces and aParentFrame is a tabular container
           // according to rule 1.3 of CSS 2.1 Sec 17.2.1. (Being a tabular container
           // pretty much means ourParentType != eTypeBlock besides the eTypeColGroup case,
           // which won't reach here.)
           if ((trailingSpaces && ourParentType != eTypeBlock) ||
               (!trailingSpaces && spaceEndIter.item().DesiredParentType() !=
                eTypeBlock)) {
             bool updateStart = (iter == endIter);
             endIter.DeleteItemsTo(spaceEndIter);
             NS_ASSERTION(trailingSpaces == endIter.IsDone(), "These should match");
             if (updateStart) {
               iter = endIter;
             }
             if (trailingSpaces) {
               break; /* Found group end */
             }
             if (updateStart) {
               // Update groupingParentType, since it might have been eTypeBlock
               // just because of the whitespace.
               groupingParentType = iter.item().DesiredParentType();
             }
           }
         }
         // Now endIter points to a non-whitespace item or a non-droppable
         // whitespace item. In the latter case, if this is the end of the group
         // we'll traverse this whitespace again.  But it'll all just be quick
         // DesiredParentType() checks which will match ourParentType (that's
         // what it means that this is the group end), so it's OK.
         prevParentType = endIter.item().DesiredParentType();
         if (prevParentType == ourParentType) {
           // End the group at endIter.
           break;
         }
         if (ourParentType == eTypeTable &&
             (prevParentType == eTypeColGroup) !=
             (groupingParentType == eTypeColGroup)) {
           // Either we started with columns and now found something else, or vice
           // versa.  In any case, end the grouping.
           break;
         }
         // Include the whitespace we didn't drop (if any) in the group, since
         // this is not the end of the group.  Note that this doesn't change
         // prevParentType, since if we didn't drop the whitespace then we ended
         // at something that wants a block parent.
         endIter = spaceEndIter;
         endIter.Next();
       } while (!endIter.IsDone());
     }
     if (iter == endIter) {
       // Nothing to wrap here; just skipped some whitespace
       continue;
     }
     // Now group together all the items between iter and endIter.  The right
     // parent type to use depends on ourParentType.
     ParentType wrapperType;
     switch (ourParentType) {
       case eTypeBlock:
         wrapperType = eTypeTable;
         break;
       case eTypeRow:
         // The parent type for a cell is eTypeBlock, since that's what a cell
         // looks like to its kids.
         wrapperType = eTypeBlock;
         break;
       case eTypeRowGroup:
         wrapperType = eTypeRow;
         break;
       case eTypeTable:
         // Either colgroup or rowgroup, depending on what we're grouping.
         wrapperType = groupingParentType == eTypeColGroup ?
           eTypeColGroup : eTypeRowGroup;
         break;
       default:
         MOZ_CRASH("Colgroups should be suppresing non-col child items");
     }
     const PseudoParentData& pseudoData = sPseudoParentData[wrapperType];
     nsIAtom* pseudoType = *pseudoData.mPseudoType;
     nsStyleContext* parentStyle = aParentFrame->StyleContext();
     nsIContent* parentContent = aParentFrame->GetContent();
     if (pseudoType == nsCSSAnonBoxes::table &&
         parentStyle->StyleDisplay()->mDisplay == NS_STYLE_DISPLAY_INLINE) {
       pseudoType = nsCSSAnonBoxes::inlineTable;
     }
     already_AddRefed<nsStyleContext> wrapperStyle =
       mPresShell->StyleSet()->ResolveAnonymousBoxStyle(pseudoType, parentStyle);
     FrameConstructionItem* newItem =
       new FrameConstructionItem(&pseudoData.mFCData,
                                 // Use the content of our parent frame
                                 parentContent,
                                 // Lie about the tag; it doesn't matter anyway
                                 pseudoType,
                                 // The namespace does matter, however; it needs
                                 // to match that of our first child item to
                                 // match the old behavior
                                 iter.item().mNameSpaceID,
                                 // no pending binding
                                 nullptr,
                                 wrapperStyle,
                                 true, nullptr);
     // Here we're cheating a tad... technically, table-internal items should be
     // inline if aParentFrame is inline, but they'll get wrapped in an
     // inline-table in the end, so it'll all work out.  In any case, arguably
     // we don't need to maintain this state at this point... but it's better
     // to, I guess.
     newItem->mIsAllInline = newItem->mHasInlineEnds =
       newItem->mStyleContext->StyleDisplay()->IsInlineOutsideStyle();
     // Table pseudo frames always induce line boundaries around their
     // contents.
     newItem->mChildItems.SetLineBoundaryAtStart(true);
     newItem->mChildItems.SetLineBoundaryAtEnd(true);
     // The parent of the items in aItems is also the parent of the items
     // in mChildItems
     newItem->mChildItems.SetParentHasNoXBLChildren(
       aItems.ParentHasNoXBLChildren());
     // Eat up all items between |iter| and |endIter| and put them in our wrapper
     // Advances |iter| to point to |endIter|.
     iter.AppendItemsToList(endIter, newItem->mChildItems);
     iter.InsertItem(newItem);
     // Now |iter| points to the item that was the first one we didn't wrap;
     // loop and see whether we need to skip it or wrap it in something
     // different.
   } while (!iter.IsDone());
 }
 inline void
 nsCSSFrameConstructor::ConstructFramesFromItemList(nsFrameConstructorState& aState,
                                                    FrameConstructionItemList& aItems,
                                                    nsIFrame* aParentFrame,
                                                    nsFrameItems& aFrameItems)
 {
   CreateNeededTablePseudos(aState, aItems, aParentFrame);
   CreateNeededAnonFlexItems(aState, aItems, aParentFrame);
   aItems.SetTriedConstructingFrames();
   for (FCItemIterator iter(aItems); !iter.IsDone(); iter.Next()) {
     NS_ASSERTION(iter.item().DesiredParentType() == GetParentType(aParentFrame),
                  "Needed pseudos didn't get created; expect bad things");
     ConstructFramesFromItem(aState, iter, aParentFrame, aFrameItems);
   }
   NS_ASSERTION(!aState.mHavePendingPopupgroup,
                "Should have proccessed it by now");
 }
 void
 nsCSSFrameConstructor::AddFCItemsForAnonymousContent(
             nsFrameConstructorState& aState,
             nsIFrame* aFrame,
             nsTArray<nsIAnonymousContentCreator::ContentInfo>& aAnonymousItems,
             FrameConstructionItemList& aItemsToConstruct,
             uint32_t aExtraFlags)
 {
   for (uint32_t i = 0; i < aAnonymousItems.Length(); ++i) {
     nsIContent* content = aAnonymousItems[i].mContent;
 #ifdef DEBUG
     nsIAnonymousContentCreator* creator = do_QueryFrame(aFrame);
     NS_ASSERTION(!creator || !creator->CreateFrameFor(content),
                  "If you need to use CreateFrameFor, you need to call "
                  "CreateAnonymousFrames manually and not follow the standard "
                  "ProcessChildren() codepath for this frame");
 #endif
     // Assert some things about this content
     NS_ABORT_IF_FALSE(!(content->GetFlags() &
                         (NODE_DESCENDANTS_NEED_FRAMES | NODE_NEEDS_FRAME)),
                       "Should not be marked as needing frames");
     NS_ABORT_IF_FALSE(!content->IsElement() ||
                       !(content->GetFlags() & ELEMENT_ALL_RESTYLE_FLAGS),
                       "Should have no pending restyle flags");
     NS_ABORT_IF_FALSE(!content->GetPrimaryFrame(),
                       "Should have no existing frame");
     NS_ABORT_IF_FALSE(!content->IsNodeOfType(nsINode::eCOMMENT) &&
                       !content->IsNodeOfType(nsINode::ePROCESSING_INSTRUCTION),
                       "Why is someone creating garbage anonymous content");
     nsRefPtr<nsStyleContext> styleContext;
     TreeMatchContext::AutoFlexItemStyleFixupSkipper
       flexItemStyleFixupSkipper(aState.mTreeMatchContext);
     if (aAnonymousItems[i].mStyleContext) {
       styleContext = aAnonymousItems[i].mStyleContext.forget();
     } else {
       styleContext = ResolveStyleContext(aFrame, content, &aState);
     }
     nsTArray<nsIAnonymousContentCreator::ContentInfo>* anonChildren = nullptr;
     if (!aAnonymousItems[i].mChildren.IsEmpty()) {
       anonChildren = &aAnonymousItems[i].mChildren;
     }
     uint32_t flags = ITEM_ALLOW_XBL_BASE | ITEM_ALLOW_PAGE_BREAK |
                      ITEM_IS_ANONYMOUSCONTENTCREATOR_CONTENT | aExtraFlags;
     AddFrameConstructionItemsInternal(aState, content, aFrame,
                                       content->Tag(), content->GetNameSpaceID(),
                                       true, styleContext, flags,
                                       anonChildren, aItemsToConstruct);
   }
 }
 void
 nsCSSFrameConstructor::ProcessChildren(nsFrameConstructorState& aState,
                                        nsIContent*              aContent,
                                        nsStyleContext*          aStyleContext,
                                        nsIFrame*                aFrame,
                                        const bool               aCanHaveGeneratedContent,
                                        nsFrameItems&            aFrameItems,
                                        const bool               aAllowBlockStyles,
                                        PendingBinding*          aPendingBinding,
                                        nsIFrame*                aPossiblyLeafFrame)
 {
   NS_PRECONDITION(aFrame, "Must have parent frame here");
   NS_PRECONDITION(aFrame->GetContentInsertionFrame() == aFrame,
                   "Parent frame in ProcessChildren should be its own "
                   "content insertion frame");
   const uint32_t kMaxDepth = 2 * MAX_REFLOW_DEPTH;
   static_assert(kMaxDepth <= UINT16_MAX, "mCurrentDepth type is too narrow");
   AutoRestore<uint16_t> savedDepth(mCurrentDepth);
   if (mCurrentDepth != UINT16_MAX) {
     ++mCurrentDepth;
   }
   if (!aPossiblyLeafFrame) {
     aPossiblyLeafFrame = aFrame;
   }
   // XXXbz ideally, this would do all the pushing of various
   // containing blocks as needed, so callers don't have to do it...
   bool haveFirstLetterStyle = false, haveFirstLineStyle = false;
   if (aAllowBlockStyles) {
     ShouldHaveSpecialBlockStyle(aContent, aStyleContext, &haveFirstLetterStyle,
                                 &haveFirstLineStyle);
   }
   // The logic here needs to match the logic in GetFloatContainingBlock()
   nsFrameConstructorSaveState floatSaveState;
   if (ShouldSuppressFloatingOfDescendants(aFrame)) {
     aState.PushFloatContainingBlock(nullptr, floatSaveState);
   } else if (aFrame->IsFloatContainingBlock()) {
     aState.PushFloatContainingBlock(aFrame, floatSaveState);
   }
   nsFrameConstructorState::PendingBindingAutoPusher pusher(aState,
                                                            aPendingBinding);
   FrameConstructionItemList itemsToConstruct;
   // If we have first-letter or first-line style then frames can get
   // moved around so don't set these flags.
   if (aAllowBlockStyles && !haveFirstLetterStyle && !haveFirstLineStyle) {
     itemsToConstruct.SetLineBoundaryAtStart(true);
     itemsToConstruct.SetLineBoundaryAtEnd(true);
   }
   // Create any anonymous frames we need here.  This must happen before the
   // non-anonymous children are processed to ensure that popups are never
   // constructed before the popupset.
   nsAutoTArray<nsIAnonymousContentCreator::ContentInfo, 4> anonymousItems;
   GetAnonymousContent(aContent, aPossiblyLeafFrame, anonymousItems);
 #ifdef DEBUG
   for (uint32_t i = 0; i < anonymousItems.Length(); ++i) {
     NS_ABORT_IF_FALSE(anonymousItems[i].mContent->IsRootOfAnonymousSubtree(),
                       "Content should know it's an anonymous subtree");
   }
 #endif
   AddFCItemsForAnonymousContent(aState, aFrame, anonymousItems,
                                 itemsToConstruct);
   if (!aPossiblyLeafFrame->IsLeaf()) {
     // :before/:after content should have the same style context parent
     // as normal kids.
     // Note that we don't use this style context for looking up things like
     // special block styles because in some cases involving table pseudo-frames
     // it has nothing to do with the parent frame's desired behavior.
     nsStyleContext* styleContext;
     if (aCanHaveGeneratedContent) {
       aFrame->AddStateBits(NS_FRAME_MAY_HAVE_GENERATED_CONTENT);
       styleContext =
         nsFrame::CorrectStyleParentFrame(aFrame, nullptr)->StyleContext();
       // Probe for generated content before
       CreateGeneratedContentItem(aState, aFrame, aContent, styleContext,
                                  nsCSSPseudoElements::ePseudo_before,
                                  itemsToConstruct);
     }
     const bool addChildItems = MOZ_LIKELY(mCurrentDepth < kMaxDepth);
     if (!addChildItems) {
       NS_WARNING("ProcessChildren max depth exceeded");
     }
     FlattenedChildIterator iter(aContent);
     for (nsIContent* child = iter.GetNextChild(); child; child = iter.GetNextChild()) {
       // Get the parent of the content and check if it is a XBL children element
       // (if the content is a children element then parent != aContent because the
       // FlattenedChildIterator will transitively iterate through <xbl:children>
       // for default content). Push the children element as an ancestor here because
       // it does not have a frame and would not otherwise be pushed as an ancestor.
       nsIContent* parent = child->GetParent();
       MOZ_ASSERT(parent, "Parent must be non-null because we are iterating children.");
       TreeMatchContext::AutoAncestorPusher ancestorPusher(aState.mTreeMatchContext);
       if (parent != aContent && parent->IsElement()) {
         if (aState.mTreeMatchContext.mAncestorFilter.HasFilter()) {
           ancestorPusher.PushAncestorAndStyleScope(parent->AsElement());
         } else {
           ancestorPusher.PushStyleScope(parent->AsElement());
         }
       }
       // Frame construction item construction should not post
       // restyles, so removing restyle flags here is safe.
       if (child->IsElement()) {
         child->UnsetFlags(ELEMENT_ALL_RESTYLE_FLAGS);
       }
       if (addChildItems) {
         AddFrameConstructionItems(aState, child, iter.XBLInvolved(), aFrame,
                                   itemsToConstruct);
       } else {
         ClearLazyBits(child, child->GetNextSibling());
       }
     }
     itemsToConstruct.SetParentHasNoXBLChildren(!iter.XBLInvolved());
     if (aCanHaveGeneratedContent) {
       // Probe for generated content after
       CreateGeneratedContentItem(aState, aFrame, aContent, styleContext,
                                  nsCSSPseudoElements::ePseudo_after,
                                  itemsToConstruct);
     }
   } else {
     ClearLazyBits(aContent->GetFirstChild(), nullptr);
   }
   ConstructFramesFromItemList(aState, itemsToConstruct, aFrame, aFrameItems);
   NS_ASSERTION(!aAllowBlockStyles || !aFrame->IsBoxFrame(),
                "can't be both block and box");
   if (haveFirstLetterStyle) {
     WrapFramesInFirstLetterFrame(aContent, aFrame, aFrameItems);
   }
   if (haveFirstLineStyle) {
     WrapFramesInFirstLineFrame(aState, aContent, aFrame, nullptr,
                                aFrameItems);
   }
   // We might end up with first-line frames that change
   // AnyKidsNeedBlockParent() without changing itemsToConstruct, but that
   // should never happen for cases whan aFrame->IsBoxFrame().
   NS_ASSERTION(!haveFirstLineStyle || !aFrame->IsBoxFrame(),
                "Shouldn't have first-line style if we're a box");
   NS_ASSERTION(!aFrame->IsBoxFrame() ||
                itemsToConstruct.AnyItemsNeedBlockParent() ==
                  (AnyKidsNeedBlockParent(aFrameItems.FirstChild()) != nullptr),
                "Something went awry in our block parent calculations");
   if (aFrame->IsBoxFrame() && itemsToConstruct.AnyItemsNeedBlockParent()) {
     // XXXbz we could do this on the FrameConstructionItemList level,
     // no?  And if we cared we could look through the item list
     // instead of groveling through the framelist here..
     nsStyleContext *frameStyleContext = aFrame->StyleContext();
     // Report a warning for non-GC frames, for chrome:
     if (!aFrame->IsGeneratedContentFrame() &&
         mPresShell->GetPresContext()->IsChrome()) {
       nsIContent *badKid = AnyKidsNeedBlockParent(aFrameItems.FirstChild());
       nsDependentAtomString parentTag(aContent->Tag()), kidTag(badKid->Tag());
       const char16_t* params[] = { parentTag.get(), kidTag.get() };
       const nsStyleDisplay *display = frameStyleContext->StyleDisplay();
       const char *message =
         (display->mDisplay == NS_STYLE_DISPLAY_INLINE_BOX)
           ? "NeededToWrapXULInlineBox" : "NeededToWrapXUL";
       nsContentUtils::ReportToConsole(nsIScriptError::warningFlag,
                                       NS_LITERAL_CSTRING("FrameConstructor"),
                                       mDocument,
                                       nsContentUtils::eXUL_PROPERTIES,
                                       message,
                                       params, ArrayLength(params));
     }
     nsRefPtr<nsStyleContext> blockSC = mPresShell->StyleSet()->
       ResolveAnonymousBoxStyle(nsCSSAnonBoxes::mozXULAnonymousBlock,
                                frameStyleContext);
     nsIFrame *blockFrame = NS_NewBlockFrame(mPresShell, blockSC);
     // We might, in theory, want to set NS_BLOCK_FLOAT_MGR and
     // NS_BLOCK_MARGIN_ROOT, but I think it's a bad idea given that
     // a real block placed here wouldn't get those set on it.
     InitAndRestoreFrame(aState, aContent, aFrame, blockFrame, false);
     NS_ASSERTION(!blockFrame->HasView(), "need to do view reparenting");
     ReparentFrames(this, blockFrame, aFrameItems);
     blockFrame->SetInitialChildList(kPrincipalList, aFrameItems);
     NS_ASSERTION(aFrameItems.IsEmpty(), "How did that happen?");
     aFrameItems.Clear();
     aFrameItems.AddChild(blockFrame);
     aFrame->AddStateBits(NS_STATE_BOX_WRAPS_KIDS_IN_BLOCK);
   }
 }
 //----------------------------------------------------------------------
 // Support for :first-line style
 // Special routine to handle placing a list of frames into a block
 // frame that has first-line style. The routine ensures that the first
 // collection of inline frames end up in a first-line frame.
 // NOTE: aState may have containing block information related to a
 // different part of the frame tree than where the first line occurs.
 // In particular aState may be set up for where ContentInserted or
 // ContentAppended is inserting content, which may be some
 // non-first-in-flow continuation of the block to which the first-line
 // belongs. So this function needs to be careful about how it uses
 // aState.
 void
 nsCSSFrameConstructor::WrapFramesInFirstLineFrame(
   nsFrameConstructorState& aState,
   nsIContent*              aBlockContent,
   nsIFrame*                aBlockFrame,
   nsIFrame*                aLineFrame,
   nsFrameItems&            aFrameItems)
 {
   // Find the part of aFrameItems that we want to put in the first-line
   nsFrameList::FrameLinkEnumerator link(aFrameItems);
   while (!link.AtEnd() && link.NextFrame()->IsInlineOutside()) {
     link.Next();
   }
   nsFrameList firstLineChildren = aFrameItems.ExtractHead(link);
   if (firstLineChildren.IsEmpty()) {
     // Nothing is supposed to go into the first-line; nothing to do
     return;
   }
   if (!aLineFrame) {
     // Create line frame
     nsStyleContext* parentStyle =
       nsFrame::CorrectStyleParentFrame(aBlockFrame,
                                        nsCSSPseudoElements::firstLine)->
         StyleContext();
     nsRefPtr<nsStyleContext> firstLineStyle = GetFirstLineStyle(aBlockContent,
                                                                 parentStyle);
     aLineFrame = NS_NewFirstLineFrame(mPresShell, firstLineStyle);
     // Initialize the line frame
     InitAndRestoreFrame(aState, aBlockContent, aBlockFrame, aLineFrame);
     // The lineFrame will be the block's first child; the rest of the
     // frame list (after lastInlineFrame) will be the second and
     // subsequent children; insert lineFrame into aFrameItems.
     aFrameItems.InsertFrame(nullptr, nullptr, aLineFrame);
     NS_ASSERTION(aLineFrame->StyleContext() == firstLineStyle,
                  "Bogus style context on line frame");
   }
   // Give the inline frames to the lineFrame <b>after</b> reparenting them
   ReparentFrames(this, aLineFrame, firstLineChildren);
   if (aLineFrame->PrincipalChildList().IsEmpty() &&
       (aLineFrame->GetStateBits() & NS_FRAME_FIRST_REFLOW)) {
     aLineFrame->SetInitialChildList(kPrincipalList, firstLineChildren);
   } else {
     AppendFrames(aLineFrame, kPrincipalList, firstLineChildren);
   }
 }
 // Special routine to handle appending a new frame to a block frame's
 // child list. Takes care of placing the new frame into the right
 // place when first-line style is present.
 void
 nsCSSFrameConstructor::AppendFirstLineFrames(
   nsFrameConstructorState& aState,
   nsIContent*              aBlockContent,
   nsIFrame*                aBlockFrame,
   nsFrameItems&            aFrameItems)
 {
   // It's possible that aBlockFrame needs to have a first-line frame
   // created because it doesn't currently have any children.
   const nsFrameList& blockKids = aBlockFrame->PrincipalChildList();
   if (blockKids.IsEmpty()) {
     WrapFramesInFirstLineFrame(aState, aBlockContent,
                                aBlockFrame, nullptr, aFrameItems);
     return;
   }
   // Examine the last block child - if it's a first-line frame then
   // appended frames need special treatment.
   nsIFrame* lastBlockKid = blockKids.LastChild();
   if (lastBlockKid->GetType() != nsGkAtoms::lineFrame) {
     // No first-line frame at the end of the list, therefore there is
     // an intervening block between any first-line frame the frames
     // we are appending. Therefore, we don't need any special
     // treatment of the appended frames.
     return;
   }
   WrapFramesInFirstLineFrame(aState, aBlockContent, aBlockFrame,
                              lastBlockKid, aFrameItems);
 }
 // Special routine to handle inserting a new frame into a block
 // frame's child list. Takes care of placing the new frame into the
 // right place when first-line style is present.
 nsresult
 nsCSSFrameConstructor::InsertFirstLineFrames(
   nsFrameConstructorState& aState,
   nsIContent*              aContent,
   nsIFrame*                aBlockFrame,
   nsIFrame**               aParentFrame,
   nsIFrame*                aPrevSibling,
   nsFrameItems&            aFrameItems)
 {
   nsresult rv = NS_OK;
   // XXXbz If you make this method actually do something, check to
   // make sure that the caller is passing what you expect.  In
   // particular, which content is aContent?  And audit the rest of
   // this code too; it makes bogus assumptions and may not build.
 #if 0
   nsIFrame* parentFrame = *aParentFrame;
   nsIFrame* newFrame = aFrameItems.childList;
   bool isInline = IsInlineOutside(newFrame);
   if (!aPrevSibling) {
     // Insertion will become the first frame. Two cases: we either
     // already have a first-line frame or we don't.
     nsIFrame* firstBlockKid = aBlockFrame->GetFirstPrincipalChild();
     if (firstBlockKid->GetType() == nsGkAtoms::lineFrame) {
       // We already have a first-line frame
       nsIFrame* lineFrame = firstBlockKid;
       if (isInline) {
         // Easy case: the new inline frame will go into the lineFrame.
         ReparentFrame(this, lineFrame, newFrame);
         InsertFrames(lineFrame, kPrincipalList, nullptr, newFrame);
         // Since the frame is going into the lineFrame, don't let it
         // go into the block too.
         aFrameItems.childList = nullptr;
         aFrameItems.lastChild = nullptr;
       }
       else {
         // Harder case: We are about to insert a block level element
         // before the first-line frame.
         // XXX need a method to steal away frames from the line-frame
       }
     }
     else {
       // We do not have a first-line frame
       if (isInline) {
         // We now need a first-line frame to contain the inline frame.
         nsIFrame* lineFrame = NS_NewFirstLineFrame(firstLineStyle);
         if (NS_SUCCEEDED(rv)) {
           // Lookup first-line style context
           nsStyleContext* parentStyle =
             nsFrame::CorrectStyleParentFrame(aBlockFrame,
                                              nsCSSPseudoElements::firstLine)->
               StyleContext();
           nsRefPtr<nsStyleContext> firstLineStyle =
             GetFirstLineStyle(aContent, parentStyle);
           // Initialize the line frame
           InitAndRestoreFrame(aState, aContent, aBlockFrame, lineFrame);
           // Make sure the caller inserts the lineFrame into the
           // blocks list of children.
           aFrameItems.childList = lineFrame;
           aFrameItems.lastChild = lineFrame;
           // Give the inline frames to the lineFrame <b>after</b>
           // reparenting them
           NS_ASSERTION(lineFrame->StyleContext() == firstLineStyle,
                        "Bogus style context on line frame");
           ReparentFrame(aPresContext, lineFrame, newFrame);
           lineFrame->SetInitialChildList(kPrincipalList, newFrame);
         }
       }
       else {
         // Easy case: the regular insertion logic can insert the new
         // frame because it's a block frame.
       }
     }
   }
   else {
     // Insertion will not be the first frame.
     nsIFrame* prevSiblingParent = aPrevSibling->GetParent();
     if (prevSiblingParent == aBlockFrame) {
       // Easy case: The prev-siblings parent is the block
       // frame. Therefore the prev-sibling is not currently in a
       // line-frame. Therefore the new frame which is going after it,
       // regardless of type, is not going into a line-frame.
     }
     else {
       // If the prevSiblingParent is not the block-frame then it must
       // be a line-frame (if it were a letter-frame, that logic would
       // already have adjusted the prev-sibling to be the
       // letter-frame).
       if (isInline) {
         // Easy case: the insertion can go where the caller thinks it
         // should go (which is into prevSiblingParent).
       }
       else {
         // Block elements don't end up in line-frames, therefore
         // change the insertion point to aBlockFrame. However, there
         // might be more inline elements following aPrevSibling that
         // need to be pulled out of the line-frame and become children
         // of the block.
         nsIFrame* nextSibling = aPrevSibling->GetNextSibling();
         nsIFrame* nextLineFrame = prevSiblingParent->GetNextInFlow();
         if (nextSibling || nextLineFrame) {
           // Oy. We have work to do. Create a list of the new frames
           // that are going into the block by stripping them away from
           // the line-frame(s).
           if (nextSibling) {
             nsLineFrame* lineFrame = (nsLineFrame*) prevSiblingParent;
             nsFrameList tail = lineFrame->StealFramesAfter(aPrevSibling);
             // XXX do something with 'tail'
           }
           nsLineFrame* nextLineFrame = (nsLineFrame*) lineFrame;
           for (;;) {
             nextLineFrame = nextLineFrame->GetNextInFlow();
             if (!nextLineFrame) {
               break;
             }
             nsIFrame* kids = nextLineFrame->GetFirstPrincipalChild();
           }
         }
         else {
           // We got lucky: aPrevSibling was the last inline frame in
           // the line-frame.
           ReparentFrame(this, aBlockFrame, newFrame);
           InsertFrames(aBlockFrame, kPrincipalList,
                        prevSiblingParent, newFrame);
           aFrameItems.childList = nullptr;
           aFrameItems.lastChild = nullptr;
         }
       }
     }
   }
 #endif
   return rv;
 }
 //----------------------------------------------------------------------
 // First-letter support
 // Determine how many characters in the text fragment apply to the
 // first letter
 static int32_t
 FirstLetterCount(const nsTextFragment* aFragment)
 {
   int32_t count = 0;
   int32_t firstLetterLength = 0;
   int32_t i, n = aFragment->GetLength();
   for (i = 0; i < n; i++) {
     char16_t ch = aFragment->CharAt(i);
     // FIXME: take content language into account when deciding whitespace.
     if (dom::IsSpaceCharacter(ch)) {
       if (firstLetterLength) {
         break;
       }
       count++;
       continue;
     }
     // XXX I18n
     if ((ch == '\'') || (ch == '\"')) {
       if (firstLetterLength) {
         break;
       }
       // keep looping
       firstLetterLength = 1;
     }
     else {
       count++;
       break;
     }
   }
   return count;
 }
 static bool
 NeedFirstLetterContinuation(nsIContent* aContent)
 {
   NS_PRECONDITION(aContent, "null ptr");
   bool result = false;
   if (aContent) {
     const nsTextFragment* frag = aContent->GetText();
     if (frag) {
       int32_t flc = FirstLetterCount(frag);
       int32_t tl = frag->GetLength();
       if (flc < tl) {
         result = true;
       }
     }
   }
   return result;
 }
 static bool IsFirstLetterContent(nsIContent* aContent)
 {
   return aContent->TextLength() &&
          !aContent->TextIsOnlyWhitespace();
 }
 /**
  * Create a letter frame, only make it a floating frame.
  */
 void
 nsCSSFrameConstructor::CreateFloatingLetterFrame(
   nsFrameConstructorState& aState,
   nsIFrame* aBlockFrame,
   nsIContent* aTextContent,
   nsIFrame* aTextFrame,
   nsIContent* aBlockContent,
   nsIFrame* aParentFrame,
   nsStyleContext* aStyleContext,
   nsFrameItems& aResult)
 {
   // Create the first-letter-frame
   nsIFrame* letterFrame;
   nsStyleSet *styleSet = mPresShell->StyleSet();
   letterFrame = NS_NewFirstLetterFrame(mPresShell, aStyleContext);
   // We don't want to use a text content for a non-text frame (because we want
   // its primary frame to be a text frame).  So use its parent for the
   // first-letter.
   nsIContent* letterContent = aTextContent->GetParent();
   nsIFrame* containingBlock = aState.GetGeometricParent(
     aStyleContext->StyleDisplay(), aParentFrame);
   InitAndRestoreFrame(aState, letterContent, containingBlock, letterFrame);
   // Init the text frame to refer to the letter frame. Make sure we
   // get a proper style context for it (the one passed in is for the
   // letter frame and will have the float property set on it; the text
   // frame shouldn't have that set).
   nsRefPtr<nsStyleContext> textSC;
   textSC = styleSet->ResolveStyleForNonElement(aStyleContext);
   aTextFrame->SetStyleContextWithoutNotification(textSC);
   InitAndRestoreFrame(aState, aTextContent, letterFrame, aTextFrame);
   // And then give the text frame to the letter frame
   SetInitialSingleChild(letterFrame, aTextFrame);
   // See if we will need to continue the text frame (does it contain
   // more than just the first-letter text or not?) If it does, then we
   // create (in advance) a continuation frame for it.
   nsIFrame* nextTextFrame = nullptr;
   if (NeedFirstLetterContinuation(aTextContent)) {
     // Create continuation
     nextTextFrame =
       CreateContinuingFrame(aState.mPresContext, aTextFrame, aParentFrame);
     // Repair the continuations style context
     nsStyleContext* parentStyleContext = aStyleContext->GetParent();
     if (parentStyleContext) {
       nsRefPtr<nsStyleContext> newSC;
       newSC = styleSet->ResolveStyleForNonElement(parentStyleContext);
       nextTextFrame->SetStyleContext(newSC);
     }
   }
   NS_ASSERTION(aResult.IsEmpty(), "aResult should be an empty nsFrameItems!");
   // Put the new float before any of the floats in the block we're doing
   // first-letter for, that is, before any floats whose parent is
   // containingBlock.
   nsFrameList::FrameLinkEnumerator link(aState.mFloatedItems);
   while (!link.AtEnd() && link.NextFrame()->GetParent() != containingBlock) {
     link.Next();
   }
   aState.AddChild(letterFrame, aResult, letterContent, aStyleContext,
                   aParentFrame, false, true, false, true,
                   link.PrevFrame());
   if (nextTextFrame) {
     aResult.AddChild(nextTextFrame);
   }
 }
 /**
  * Create a new letter frame for aTextFrame. The letter frame will be
  * a child of aParentFrame.
  */
 void
 nsCSSFrameConstructor::CreateLetterFrame(nsIFrame* aBlockFrame,
                                          nsIFrame* aBlockContinuation,
                                          nsIContent* aTextContent,
                                          nsIFrame* aParentFrame,
                                          nsFrameItems& aResult)
 {
   NS_PRECONDITION(aTextContent->IsNodeOfType(nsINode::eTEXT),
                   "aTextContent isn't text");
   NS_ASSERTION(nsLayoutUtils::GetAsBlock(aBlockFrame),
                  "Not a block frame?");
   // Get style context for the first-letter-frame
   nsStyleContext* parentStyleContext =
     nsFrame::CorrectStyleParentFrame(aParentFrame,
                                      nsCSSPseudoElements::firstLetter)->
       StyleContext();
   // Use content from containing block so that we can actually
   // find a matching style rule.
   nsIContent* blockContent = aBlockFrame->GetContent();
   // Create first-letter style rule
   nsRefPtr<nsStyleContext> sc = GetFirstLetterStyle(blockContent,
                                                     parentStyleContext);
   if (sc) {
     nsRefPtr<nsStyleContext> textSC;
     textSC = mPresShell->StyleSet()->ResolveStyleForNonElement(sc);
     // Create a new text frame (the original one will be discarded)
     // pass a temporary stylecontext, the correct one will be set
     // later.  Start off by unsetting the primary frame for
     // aTextContent, so it's no longer pointing to the to-be-destroyed
     // frame.
     // XXXbz it would be really nice to destroy the old frame _first_,
     // then create the new one, so we could avoid this hack.
     aTextContent->SetPrimaryFrame(nullptr);
     nsIFrame* textFrame = NS_NewTextFrame(mPresShell, textSC);
     NS_ASSERTION(aBlockContinuation == GetFloatContainingBlock(aParentFrame),
                  "Containing block is confused");
     nsFrameConstructorState state(mPresShell,
                                   GetAbsoluteContainingBlock(aParentFrame, FIXED_POS),
                                   GetAbsoluteContainingBlock(aParentFrame, ABS_POS),
                                   aBlockContinuation);
     // Create the right type of first-letter frame
     const nsStyleDisplay* display = sc->StyleDisplay();
     if (display->IsFloatingStyle() && !aParentFrame->IsSVGText()) {
       // Make a floating first-letter frame
       CreateFloatingLetterFrame(state, aBlockFrame, aTextContent, textFrame,
                                 blockContent, aParentFrame, sc, aResult);
     }
     else {
       // Make an inflow first-letter frame
       nsIFrame* letterFrame = NS_NewFirstLetterFrame(mPresShell, sc);
       // Initialize the first-letter-frame.  We don't want to use a text
       // content for a non-text frame (because we want its primary frame to
       // be a text frame).  So use its parent for the first-letter.
       nsIContent* letterContent = aTextContent->GetParent();
       letterFrame->Init(letterContent, aParentFrame, nullptr);
       InitAndRestoreFrame(state, aTextContent, letterFrame, textFrame);
       SetInitialSingleChild(letterFrame, textFrame);
       aResult.Clear();
       aResult.AddChild(letterFrame);
       NS_ASSERTION(!aBlockFrame->GetPrevContinuation(),
                    "should have the first continuation here");
       aBlockFrame->AddStateBits(NS_BLOCK_HAS_FIRST_LETTER_CHILD);
     }
     aTextContent->SetPrimaryFrame(textFrame);
   }
 }
 void
 nsCSSFrameConstructor::WrapFramesInFirstLetterFrame(
   nsIContent*              aBlockContent,
   nsIFrame*                aBlockFrame,
   nsFrameItems&            aBlockFrames)
 {
   aBlockFrame->AddStateBits(NS_BLOCK_HAS_FIRST_LETTER_STYLE);
   nsIFrame* parentFrame = nullptr;
   nsIFrame* textFrame = nullptr;
   nsIFrame* prevFrame = nullptr;
   nsFrameItems letterFrames;
   bool stopLooking = false;
   WrapFramesInFirstLetterFrame(aBlockFrame, aBlockFrame, aBlockFrame,
                                aBlockFrames.FirstChild(),
                                &parentFrame, &textFrame, &prevFrame,
                                letterFrames, &stopLooking);
   if (parentFrame) {
     if (parentFrame == aBlockFrame) {
       // Take textFrame out of the block's frame list and substitute the
       // letter frame(s) instead.
       aBlockFrames.DestroyFrame(textFrame);
       aBlockFrames.InsertFrames(nullptr, prevFrame, letterFrames);
     }
     else {
       // Take the old textFrame out of the inline parent's child list
       RemoveFrame(kPrincipalList, textFrame);
       // Insert in the letter frame(s)
       parentFrame->InsertFrames(kPrincipalList, prevFrame, letterFrames);
     }
   }
 }
 void
 nsCSSFrameConstructor::WrapFramesInFirstLetterFrame(
   nsIFrame*                aBlockFrame,
   nsIFrame*                aBlockContinuation,
   nsIFrame*                aParentFrame,
   nsIFrame*                aParentFrameList,
   nsIFrame**               aModifiedParent,
   nsIFrame**               aTextFrame,
   nsIFrame**               aPrevFrame,
   nsFrameItems&            aLetterFrames,
   bool*                  aStopLooking)
 {
   nsIFrame* prevFrame = nullptr;
   nsIFrame* frame = aParentFrameList;
   while (frame) {
     nsIFrame* nextFrame = frame->GetNextSibling();
     nsIAtom* frameType = frame->GetType();
     if (nsGkAtoms::textFrame == frameType) {
       // Wrap up first-letter content in a letter frame
       nsIContent* textContent = frame->GetContent();
       if (IsFirstLetterContent(textContent)) {
         // Create letter frame to wrap up the text
         CreateLetterFrame(aBlockFrame, aBlockContinuation, textContent,
                           aParentFrame, aLetterFrames);
         // Provide adjustment information for parent
         *aModifiedParent = aParentFrame;
         *aTextFrame = frame;
         *aPrevFrame = prevFrame;
         *aStopLooking = true;
         return;
       }
     }
     else if (IsInlineFrame(frame) && frameType != nsGkAtoms::brFrame) {
       nsIFrame* kids = frame->GetFirstPrincipalChild();
       WrapFramesInFirstLetterFrame(aBlockFrame, aBlockContinuation, frame,
                                    kids, aModifiedParent, aTextFrame,
                                    aPrevFrame, aLetterFrames, aStopLooking);
       if (*aStopLooking) {
         return;
       }
     }
     else {
       // This will stop us looking to create more letter frames. For
       // example, maybe the frame-type is "letterFrame" or
       // "placeholderFrame". This keeps us from creating extra letter
       // frames, and also prevents us from creating letter frames when
       // the first real content child of a block is not text (e.g. an
       // image, hr, etc.)
       *aStopLooking = true;
       break;
     }
     prevFrame = frame;
     frame = nextFrame;
   }
 }
 static nsIFrame*
 FindFirstLetterFrame(nsIFrame* aFrame, nsIFrame::ChildListID aListID)
 {
   nsFrameList list = aFrame->GetChildList(aListID);
   for (nsFrameList::Enumerator e(list); !e.AtEnd(); e.Next()) {
     if (nsGkAtoms::letterFrame == e.get()->GetType()) {
       return e.get();
     }
   }
   return nullptr;
 }
 nsresult
 nsCSSFrameConstructor::RemoveFloatingFirstLetterFrames(
   nsPresContext* aPresContext,
   nsIPresShell* aPresShell,
   nsIFrame* aBlockFrame,
   bool* aStopLooking)
 {
   // Look for the first letter frame on the kFloatList, then kPushedFloatsList.
   nsIFrame* floatFrame =
     ::FindFirstLetterFrame(aBlockFrame, nsIFrame::kFloatList);
   if (!floatFrame) {
     floatFrame =
       ::FindFirstLetterFrame(aBlockFrame, nsIFrame::kPushedFloatsList);
     if (!floatFrame) {
       return NS_OK;
     }
   }
   // Take the text frame away from the letter frame (so it isn't
   // destroyed when we destroy the letter frame).
   nsIFrame* textFrame = floatFrame->GetFirstPrincipalChild();
   if (!textFrame) {
     return NS_OK;
   }
   // Discover the placeholder frame for the letter frame
   nsIFrame* parentFrame;
   nsPlaceholderFrame* placeholderFrame = GetPlaceholderFrameFor(floatFrame);
   if (!placeholderFrame) {
     // Somethings really wrong
     return NS_OK;
   }
   parentFrame = placeholderFrame->GetParent();
   if (!parentFrame) {
     // Somethings really wrong
     return NS_OK;
   }
   // Create a new text frame with the right style context that maps
   // all of the content that was previously part of the letter frame
   // (and probably continued elsewhere).
   nsStyleContext* parentSC = parentFrame->StyleContext();
   nsIContent* textContent = textFrame->GetContent();
   if (!textContent) {
     return NS_OK;
   }
   nsRefPtr<nsStyleContext> newSC;
   newSC = aPresShell->StyleSet()->ResolveStyleForNonElement(parentSC);
   nsIFrame* newTextFrame = NS_NewTextFrame(aPresShell, newSC);
   newTextFrame->Init(textContent, parentFrame, nullptr);
   // Destroy the old text frame's continuations (the old text frame
   // will be destroyed when its letter frame is destroyed).
   nsIFrame* frameToDelete = textFrame->LastContinuation();
   while (frameToDelete != textFrame) {
     nsIFrame* nextFrameToDelete = frameToDelete->GetPrevContinuation();
     RemoveFrame(kPrincipalList, frameToDelete);
     frameToDelete = nextFrameToDelete;
   }
   nsIFrame* prevSibling = placeholderFrame->GetPrevSibling();
   // Now that everything is set...
 #ifdef NOISY_FIRST_LETTER
   printf("RemoveFloatingFirstLetterFrames: textContent=%p oldTextFrame=%p newTextFrame=%p\n",
          textContent.get(), textFrame, newTextFrame);
 #endif
   // Remove placeholder frame and the float
   RemoveFrame(kPrincipalList, placeholderFrame);
   // Now that the old frames are gone, we can start pointing to our
   // new primary frame.
   textContent->SetPrimaryFrame(newTextFrame);
   // Wallpaper bug 822910.
   bool offsetsNeedFixing =
     prevSibling && prevSibling->GetType() == nsGkAtoms::textFrame;
   if (offsetsNeedFixing) {
     prevSibling->AddStateBits(TEXT_OFFSETS_NEED_FIXING);
   }
   // Insert text frame in its place
   nsFrameList textList(newTextFrame, newTextFrame);
   InsertFrames(parentFrame, kPrincipalList, prevSibling, textList);
   if (offsetsNeedFixing) {
     prevSibling->RemoveStateBits(TEXT_OFFSETS_NEED_FIXING);
   }
   return NS_OK;
 }
 nsresult
 nsCSSFrameConstructor::RemoveFirstLetterFrames(nsPresContext* aPresContext,
                                                nsIPresShell* aPresShell,
                                                nsIFrame* aFrame,
                                                nsIFrame* aBlockFrame,
                                                bool* aStopLooking)
 {
   nsIFrame* prevSibling = nullptr;
   nsIFrame* kid = aFrame->GetFirstPrincipalChild();
   while (kid) {
     if (nsGkAtoms::letterFrame == kid->GetType()) {
       // Bingo. Found it. First steal away the text frame.
       nsIFrame* textFrame = kid->GetFirstPrincipalChild();
       if (!textFrame) {
         break;
       }
       // Create a new textframe
       nsStyleContext* parentSC = aFrame->StyleContext();
       if (!parentSC) {
         break;
       }
       nsIContent* textContent = textFrame->GetContent();
       if (!textContent) {
         break;
       }
       nsRefPtr<nsStyleContext> newSC;
       newSC = aPresShell->StyleSet()->ResolveStyleForNonElement(parentSC);
       textFrame = NS_NewTextFrame(aPresShell, newSC);
       textFrame->Init(textContent, aFrame, nullptr);
       // Next rip out the kid and replace it with the text frame
       RemoveFrame(kPrincipalList, kid);
       // Now that the old frames are gone, we can start pointing to our
       // new primary frame.
       textContent->SetPrimaryFrame(textFrame);
       // Wallpaper bug 822910.
       bool offsetsNeedFixing =
         prevSibling && prevSibling->GetType() == nsGkAtoms::textFrame;
       if (offsetsNeedFixing) {
         prevSibling->AddStateBits(TEXT_OFFSETS_NEED_FIXING);
       }
       // Insert text frame in its place
       nsFrameList textList(textFrame, textFrame);
       InsertFrames(aFrame, kPrincipalList, prevSibling, textList);
       if (offsetsNeedFixing) {
         prevSibling->RemoveStateBits(TEXT_OFFSETS_NEED_FIXING);
       }
       *aStopLooking = true;
       NS_ASSERTION(!aBlockFrame->GetPrevContinuation(),
                    "should have the first continuation here");
       aBlockFrame->RemoveStateBits(NS_BLOCK_HAS_FIRST_LETTER_CHILD);
       break;
     }
     else if (IsInlineFrame(kid)) {
       // Look inside child inline frame for the letter frame
       RemoveFirstLetterFrames(aPresContext, aPresShell,
                               kid, aBlockFrame, aStopLooking);
       if (*aStopLooking) {
         break;
       }
     }
     prevSibling = kid;
     kid = kid->GetNextSibling();
   }
   return NS_OK;
 }
 nsresult
 nsCSSFrameConstructor::RemoveLetterFrames(nsPresContext* aPresContext,
                                           nsIPresShell* aPresShell,
                                           nsIFrame* aBlockFrame)
 {
   aBlockFrame = aBlockFrame->FirstContinuation();
   nsIFrame* continuation = aBlockFrame;
   bool stopLooking = false;
   nsresult rv;
   do {
     rv = RemoveFloatingFirstLetterFrames(aPresContext, aPresShell,
                                          continuation, &stopLooking);
     if (NS_SUCCEEDED(rv) && !stopLooking) {
       rv = RemoveFirstLetterFrames(aPresContext, aPresShell,
                                    continuation, aBlockFrame, &stopLooking);
     }
     if (stopLooking) {
       break;
     }
     continuation = continuation->GetNextContinuation();
   }  while (continuation);
   return rv;
 }
 // Fixup the letter frame situation for the given block
 void
 nsCSSFrameConstructor::RecoverLetterFrames(nsIFrame* aBlockFrame)
 {
   aBlockFrame = aBlockFrame->FirstContinuation();
   nsIFrame* continuation = aBlockFrame;
   nsIFrame* parentFrame = nullptr;
   nsIFrame* textFrame = nullptr;
   nsIFrame* prevFrame = nullptr;
   nsFrameItems letterFrames;
   bool stopLooking = false;
   do {
     // XXX shouldn't this bit be set already (bug 408493), assert instead?
     continuation->AddStateBits(NS_BLOCK_HAS_FIRST_LETTER_STYLE);
     WrapFramesInFirstLetterFrame(aBlockFrame, continuation, continuation,
                                  continuation->GetFirstPrincipalChild(),
                                  &parentFrame, &textFrame, &prevFrame,
                                  letterFrames, &stopLooking);
     if (stopLooking) {
       break;
     }
     continuation = continuation->GetNextContinuation();
   } while (continuation);
   if (parentFrame) {
     // Take the old textFrame out of the parents child list
     RemoveFrame(kPrincipalList, textFrame);
     // Insert in the letter frame(s)
     parentFrame->InsertFrames(kPrincipalList, prevFrame, letterFrames);
   }
 }
 //----------------------------------------------------------------------
 // listbox Widget Routines
 nsresult
 nsCSSFrameConstructor::CreateListBoxContent(nsPresContext* aPresContext,
                                             nsIFrame*       aParentFrame,
                                             nsIFrame*       aPrevFrame,
                                             nsIContent*     aChild,
                                             nsIFrame**      aNewFrame,
                                             bool            aIsAppend,
                                             bool            aIsScrollbar,
                                             nsILayoutHistoryState* aFrameState)
 {
 #ifdef MOZ_XUL
   nsresult rv = NS_OK;
   // Construct a new frame
   if (nullptr != aParentFrame) {
     nsFrameItems            frameItems;
     nsFrameConstructorState state(mPresShell, GetAbsoluteContainingBlock(aParentFrame, FIXED_POS),
                                   GetAbsoluteContainingBlock(aParentFrame, ABS_POS),
                                   GetFloatContainingBlock(aParentFrame),
                                   mTempFrameTreeState);
     // If we ever initialize the ancestor filter on |state|, make sure
     // to push the right parent!
     nsRefPtr<nsStyleContext> styleContext;
     styleContext = ResolveStyleContext(aParentFrame, aChild, &state);
     // Pre-check for display "none" - only if we find that, do we create
     // any frame at all
     const nsStyleDisplay* display = styleContext->StyleDisplay();
     if (NS_STYLE_DISPLAY_NONE == display->mDisplay) {
       *aNewFrame = nullptr;
       return NS_OK;
     }
     BeginUpdate();
     FrameConstructionItemList items;
     AddFrameConstructionItemsInternal(state, aChild, aParentFrame,
                                       aChild->Tag(), aChild->GetNameSpaceID(),
                                       true, styleContext,
                                       ITEM_ALLOW_XBL_BASE, nullptr, items);
     ConstructFramesFromItemList(state, items, aParentFrame, frameItems);
     nsIFrame* newFrame = frameItems.FirstChild();
     *aNewFrame = newFrame;
     if (newFrame) {
       // Notify the parent frame
       if (aIsAppend)
         rv = ((nsListBoxBodyFrame*)aParentFrame)->ListBoxAppendFrames(frameItems);
       else
         rv = ((nsListBoxBodyFrame*)aParentFrame)->ListBoxInsertFrames(aPrevFrame, frameItems);
     }
     EndUpdate();
 #ifdef ACCESSIBILITY
     if (newFrame) {
       nsAccessibilityService* accService = nsIPresShell::AccService();
       if (accService) {
         accService->ContentRangeInserted(mPresShell, aChild->GetParent(),
                                          aChild, aChild->GetNextSibling());
       }
     }
 #endif
   }
   return rv;
 #else
   return NS_ERROR_FAILURE;
 #endif
 }
 //----------------------------------------
 void
 nsCSSFrameConstructor::ConstructBlock(nsFrameConstructorState& aState,
                                       const nsStyleDisplay*    aDisplay,
                                       nsIContent*              aContent,
                                       nsIFrame*                aParentFrame,
                                       nsIFrame*                aContentParentFrame,
                                       nsStyleContext*          aStyleContext,
                                       nsIFrame**               aNewFrame,
                                       nsFrameItems&            aFrameItems,
                                       nsIFrame*                aPositionedFrameForAbsPosContainer,
                                       PendingBinding*          aPendingBinding)
 {
   // Create column wrapper if necessary
   nsIFrame* blockFrame = *aNewFrame;
   NS_ASSERTION(blockFrame->GetType() == nsGkAtoms::blockFrame, "not a block frame?");
   nsIFrame* parent = aParentFrame;
   nsRefPtr<nsStyleContext> blockStyle = aStyleContext;
   const nsStyleColumn* columns = aStyleContext->StyleColumn();
   if (columns->mColumnCount != NS_STYLE_COLUMN_COUNT_AUTO
       || columns->mColumnWidth.GetUnit() != eStyleUnit_Auto) {
     nsIFrame* columnSetFrame = nullptr;
     columnSetFrame =
       NS_NewColumnSetFrame(mPresShell, aStyleContext, nsFrameState(0));
     InitAndRestoreFrame(aState, aContent, aParentFrame, columnSetFrame);
     blockStyle = mPresShell->StyleSet()->
       ResolveAnonymousBoxStyle(nsCSSAnonBoxes::columnContent, aStyleContext);
     parent = columnSetFrame;
     *aNewFrame = columnSetFrame;
     SetInitialSingleChild(columnSetFrame, blockFrame);
   }
   blockFrame->SetStyleContextWithoutNotification(blockStyle);
   InitAndRestoreFrame(aState, aContent, parent, blockFrame);
   aState.AddChild(*aNewFrame, aFrameItems, aContent, aStyleContext,
                   aContentParentFrame ? aContentParentFrame :
                                         aParentFrame);
   if (!mRootElementFrame) {
     // The frame we're constructing will be the root element frame.
     // Set mRootElementFrame before processing children.
     mRootElementFrame = *aNewFrame;
   }
   // We should make the outer frame be the absolute containing block,
   // if one is required. We have to do this because absolute
   // positioning must be computed with respect to the CSS dimensions
   // of the element, which are the dimensions of the outer block. But
   // we can't really do that because only blocks can have absolute
   // children. So use the block and try to compensate with hacks
   // in nsBlockFrame::CalculateContainingBlockSizeForAbsolutes.
   nsFrameConstructorSaveState absoluteSaveState;
   (*aNewFrame)->AddStateBits(NS_FRAME_CAN_HAVE_ABSPOS_CHILDREN);
   if (aPositionedFrameForAbsPosContainer) {
     //    NS_ASSERTION(aRelPos, "should have made area frame for this");
     aState.PushAbsoluteContainingBlock(*aNewFrame, aPositionedFrameForAbsPosContainer, absoluteSaveState);
   }
   // Process the child content
   nsFrameItems childItems;
   ProcessChildren(aState, aContent, aStyleContext, blockFrame, true,
                   childItems, true, aPendingBinding);
   // Set the frame's initial child list
   blockFrame->SetInitialChildList(kPrincipalList, childItems);
 }
 nsIFrame*
 nsCSSFrameConstructor::ConstructInline(nsFrameConstructorState& aState,
                                        FrameConstructionItem&   aItem,
                                        nsIFrame*                aParentFrame,
                                        const nsStyleDisplay*    aDisplay,
                                        nsFrameItems&            aFrameItems)
 {
   // If an inline frame has non-inline kids, then we chop up the child list
   // into runs of blocks and runs of inlines, create anonymous block frames to
   // contain the runs of blocks, inline frames with our style context for the
   // runs of inlines, and put all these frames, in order, into aFrameItems.  We
   // return the the first one.  The whole setup is called an {ib}
   // split; in what follows "frames in the split" refers to the anonymous blocks
   // and inlines that contain our children.
   //
   // {ib} splits maintain the following invariants:
   // 1) All frames in the split have the NS_FRAME_PART_OF_IBSPLIT bit
   //    set.
   // 2) Each frame in the split has the nsIFrame::IBSplitSibling
   //    property pointing to the next frame in the split, except for the last
   //    one, which does not have it set.
   // 3) Each frame in the split has the nsIFrame::IBSplitPrevSibling
   //    property pointing to the previous frame in the split, except for the
   //    first one, which does not have it set.
   // 4) The first and last frame in the split are always inlines.
   //
   // An invariant that is NOT maintained is that the wrappers are actually
   // linked via GetNextSibling linkage.  A simple example is an inline
   // containing an inline that contains a block.  The three parts of the inner
   // inline end up with three different parents.
   //
   // For example, this HTML:
   // <span>
   //   <div>a</div>
   //   <span>
   //     b
   //     <div>c</div>
   //   </span>
   //   d
   //   <div>e</div>
   //   f
   //  </span>
   // Gives the following frame tree:
   //
   // Inline (outer span)
   // Block (anonymous, outer span)
   //   Block (div)
   //     Text("a")
   // Inline (outer span)
   //   Inline (inner span)
   //     Text("b")
   // Block (anonymous, outer span)
   //   Block (anonymous, inner span)
   //     Block (div)
   //       Text("c")
   // Inline (outer span)
   //   Inline (inner span)
   //   Text("d")
   // Block (anonymous, outer span)
   //   Block (div)
   //     Text("e")
   // Inline (outer span)
   //   Text("f")
   nsIContent* const content = aItem.mContent;
   nsStyleContext* const styleContext = aItem.mStyleContext;
   bool positioned =
     NS_STYLE_DISPLAY_INLINE == aDisplay->mDisplay &&
     aDisplay->IsRelativelyPositionedStyle() &&
     !aParentFrame->IsSVGText();
   nsIFrame* newFrame = NS_NewInlineFrame(mPresShell, styleContext);
   // Initialize the frame
   InitAndRestoreFrame(aState, content, aParentFrame, newFrame);
   // Inline frames can always have generated content
   newFrame->AddStateBits(NS_FRAME_MAY_HAVE_GENERATED_CONTENT);
   nsFrameConstructorSaveState absoluteSaveState;  // definition cannot be inside next block
                                                   // because the object's destructor is significant
                                                   // this is part of the fix for bug 42372
   newFrame->AddStateBits(NS_FRAME_CAN_HAVE_ABSPOS_CHILDREN);
   if (positioned) {
     // Relatively positioned frames becomes a container for child
     // frames that are positioned
     aState.PushAbsoluteContainingBlock(newFrame, newFrame, absoluteSaveState);
   }
   // Process the child content
   nsFrameItems childItems;
   ConstructFramesFromItemList(aState, aItem.mChildItems, newFrame, childItems);
   nsFrameList::FrameLinkEnumerator firstBlockEnumerator(childItems);
   if (!aItem.mIsAllInline) {
     FindFirstBlock(firstBlockEnumerator);
   }
   if (aItem.mIsAllInline || firstBlockEnumerator.AtEnd()) {
     // This part is easy.  We either already know we have no non-inline kids,
     // or haven't found any when constructing actual frames (the latter can
     // happen only if out-of-flows that we thought had no containing block
     // acquired one when ancestor inline frames and {ib} splits got
     // constructed).  Just put all the kids into the single inline frame and
     // bail.
     newFrame->SetInitialChildList(kPrincipalList, childItems);
     aState.AddChild(newFrame, aFrameItems, content, styleContext, aParentFrame);
     return newFrame;
   }
   // This inline frame contains several types of children. Therefore this frame
   // has to be chopped into several pieces, as described above.
   // Grab the first inline's kids
   nsFrameList firstInlineKids = childItems.ExtractHead(firstBlockEnumerator);
   newFrame->SetInitialChildList(kPrincipalList, firstInlineKids);
   aFrameItems.AddChild(newFrame);
   CreateIBSiblings(aState, newFrame, positioned, childItems, aFrameItems);
   return newFrame;
 }
 void
 nsCSSFrameConstructor::CreateIBSiblings(nsFrameConstructorState& aState,
                                         nsIFrame* aInitialInline,
                                         bool aIsPositioned,
                                         nsFrameItems& aChildItems,
                                         nsFrameItems& aSiblings)
 {
   nsIContent* content = aInitialInline->GetContent();
   nsStyleContext* styleContext = aInitialInline->StyleContext();
   nsIFrame* parentFrame = aInitialInline->GetParent();
   // Resolve the right style context for our anonymous blocks.
   // The distinction in styles is needed because of CSS 2.1, section
   // 9.2.1.1, which says:
   //   When such an inline box is affected by relative positioning, any
   //   resulting translation also affects the block-level box contained
   //   in the inline box.
   nsRefPtr<nsStyleContext> blockSC =
     mPresShell->StyleSet()->
       ResolveAnonymousBoxStyle(aIsPositioned ?
                                  nsCSSAnonBoxes::mozAnonymousPositionedBlock :
                                  nsCSSAnonBoxes::mozAnonymousBlock,
                                styleContext);
   nsIFrame* lastNewInline = aInitialInline->FirstContinuation();
   do {
     // On entry to this loop aChildItems is not empty and the first frame in it
     // is block-level.
     NS_PRECONDITION(aChildItems.NotEmpty(), "Should have child items");
     NS_PRECONDITION(!aChildItems.FirstChild()->IsInlineOutside(),
                     "Must have list starting with block");
     // The initial run of blocks belongs to an anonymous block that we create
     // right now. The anonymous block will be the parent of these block
     // children of the inline.
     nsIFrame* blockFrame;
     blockFrame = NS_NewBlockFrame(mPresShell, blockSC);
     InitAndRestoreFrame(aState, content, parentFrame, blockFrame, false);
     // Find the first non-block child which defines the end of our block kids
     // and the start of our next inline's kids
     nsFrameList::FrameLinkEnumerator firstNonBlock =
       FindFirstNonBlock(aChildItems);
     nsFrameList blockKids = aChildItems.ExtractHead(firstNonBlock);
     MoveChildrenTo(aState.mPresContext, aInitialInline, blockFrame, blockKids);
     SetFrameIsIBSplit(lastNewInline, blockFrame);
     aSiblings.AddChild(blockFrame);
     // Now grab the initial inlines in aChildItems and put them into an inline
     // frame
     nsIFrame* inlineFrame = NS_NewInlineFrame(mPresShell, styleContext);
     InitAndRestoreFrame(aState, content, parentFrame, inlineFrame, false);
     inlineFrame->AddStateBits(NS_FRAME_MAY_HAVE_GENERATED_CONTENT |
                               NS_FRAME_CAN_HAVE_ABSPOS_CHILDREN);
     if (aIsPositioned) {
       inlineFrame->MarkAsAbsoluteContainingBlock();
     }
     if (aChildItems.NotEmpty()) {
       nsFrameList::FrameLinkEnumerator firstBlock(aChildItems);
       FindFirstBlock(firstBlock);
       nsFrameList inlineKids = aChildItems.ExtractHead(firstBlock);
       MoveChildrenTo(aState.mPresContext, aInitialInline, inlineFrame,
                      inlineKids);
     }
     SetFrameIsIBSplit(blockFrame, inlineFrame);
     aSiblings.AddChild(inlineFrame);
     lastNewInline = inlineFrame;
   } while (aChildItems.NotEmpty());
   SetFrameIsIBSplit(lastNewInline, nullptr);
 }
 void
 nsCSSFrameConstructor::BuildInlineChildItems(nsFrameConstructorState& aState,
                                              FrameConstructionItem& aParentItem,
                                              bool aItemIsWithinSVGText,
                                              bool aItemAllowsTextPathChild)
 {
   // XXXbz should we preallocate aParentItem.mChildItems to some sane
   // length?  Maybe even to parentContent->GetChildCount()?
   nsFrameConstructorState::PendingBindingAutoPusher
     pusher(aState, aParentItem.mPendingBinding);
   nsStyleContext* const parentStyleContext = aParentItem.mStyleContext;
   nsIContent* const parentContent = aParentItem.mContent;
   TreeMatchContext::AutoAncestorPusher ancestorPusher(aState.mTreeMatchContext);
   if (aState.mTreeMatchContext.mAncestorFilter.HasFilter()) {
     ancestorPusher.PushAncestorAndStyleScope(parentContent->AsElement());
   } else {
     ancestorPusher.PushStyleScope(parentContent->AsElement());
   }
   if (!aItemIsWithinSVGText) {
     // Probe for generated content before
     CreateGeneratedContentItem(aState, nullptr, parentContent, parentStyleContext,
                                nsCSSPseudoElements::ePseudo_before,
                                aParentItem.mChildItems);
   }
   uint32_t flags = ITEM_ALLOW_XBL_BASE | ITEM_ALLOW_PAGE_BREAK;
   if (aItemIsWithinSVGText) {
     flags |= ITEM_IS_WITHIN_SVG_TEXT;
   }
   if (aItemAllowsTextPathChild && aParentItem.mIsForSVGAElement) {
     flags |= ITEM_ALLOWS_TEXT_PATH_CHILD;
   }
   if (!aParentItem.mAnonChildren.IsEmpty()) {
     // Use the anon-children list instead of the content tree child list so
     // that we use any special style context that should be associated with
     // the children, and so that we won't try to construct grandchildren frame
     // constructor items before the frame is available for their parent.
     AddFCItemsForAnonymousContent(aState, nullptr, aParentItem.mAnonChildren,
                                   aParentItem.mChildItems, flags);
   } else {
     // Use the content tree child list:
     FlattenedChildIterator iter(parentContent);
     for (nsIContent* content = iter.GetNextChild(); content; content = iter.GetNextChild()) {
       // Get the parent of the content and check if it is a XBL children element
       // (if the content is a children element then contentParent != parentContent because the
       // FlattenedChildIterator will transitively iterate through <xbl:children>
       // for default content). Push the children element as an ancestor here because
       // it does not have a frame and would not otherwise be pushed as an ancestor.
       nsIContent* contentParent = content->GetParent();
       MOZ_ASSERT(contentParent, "Parent must be non-null because we are iterating children.");
       TreeMatchContext::AutoAncestorPusher insertionPointPusher(aState.mTreeMatchContext);
       if (contentParent != parentContent && contentParent->IsElement()) {
         if (aState.mTreeMatchContext.mAncestorFilter.HasFilter()) {
           insertionPointPusher.PushAncestorAndStyleScope(contentParent->AsElement());
         } else {
           insertionPointPusher.PushStyleScope(contentParent->AsElement());
         }
       }
       // Manually check for comments/PIs, since we don't have a frame to pass to
       // AddFrameConstructionItems.  We know our parent is a non-replaced inline,
       // so there is no need to do the NeedFrameFor check.
       content->UnsetFlags(NODE_DESCENDANTS_NEED_FRAMES | NODE_NEEDS_FRAME);
       if (content->IsNodeOfType(nsINode::eCOMMENT) ||
           content->IsNodeOfType(nsINode::ePROCESSING_INSTRUCTION)) {
         continue;
       }
       if (content->IsElement()) {
         // See comment explaining why we need to remove the "is possible
         // restyle root" flags in AddFrameConstructionItems.  But note
         // that we can remove all restyle flags, just like in
         // ProcessChildren and for the same reason.
         content->UnsetFlags(ELEMENT_ALL_RESTYLE_FLAGS);
       }
       nsRefPtr<nsStyleContext> childContext =
         ResolveStyleContext(parentStyleContext, content, &aState);
       AddFrameConstructionItemsInternal(aState, content, nullptr, content->Tag(),
                                         content->GetNameSpaceID(),
                                         iter.XBLInvolved(), childContext,
                                         flags, nullptr,
                                         aParentItem.mChildItems);
     }
   }
   if (!aItemIsWithinSVGText) {
     // Probe for generated content after
     CreateGeneratedContentItem(aState, nullptr, parentContent, parentStyleContext,
                                nsCSSPseudoElements::ePseudo_after,
                                aParentItem.mChildItems);
   }
   aParentItem.mIsAllInline = aParentItem.mChildItems.AreAllItemsInline();
 }
 // return whether it's ok to append (in the AppendFrames sense) to
 // aParentFrame if our nextSibling is aNextSibling.  aParentFrame must
 // be an ib-split inline.
 static bool
 IsSafeToAppendToIBSplitInline(nsIFrame* aParentFrame, nsIFrame* aNextSibling)
 {
   NS_PRECONDITION(IsInlineFrame(aParentFrame),
                   "Must have an inline parent here");
   do {
     NS_ASSERTION(IsFramePartOfIBSplit(aParentFrame),
                  "How is this not part of an ib-split?");
     if (aNextSibling || aParentFrame->GetNextContinuation() ||
         GetIBSplitSibling(aParentFrame)) {
       return false;
     }
     aNextSibling = aParentFrame->GetNextSibling();
     aParentFrame = aParentFrame->GetParent();
   } while (IsInlineFrame(aParentFrame));
   return true;
 }
 bool
 nsCSSFrameConstructor::WipeContainingBlock(nsFrameConstructorState& aState,
                                            nsIFrame* aContainingBlock,
                                            nsIFrame* aFrame,
                                            FrameConstructionItemList& aItems,
                                            bool aIsAppend,
                                            nsIFrame* aPrevSibling)
 {
   if (aItems.IsEmpty()) {
     return false;
   }
   // Before we go and append the frames, we must check for several
   // special situations.
   // Situation #1 is a XUL frame that contains frames that are required
   // to be wrapped in blocks.
   if (aFrame->IsBoxFrame() &&
       !(aFrame->GetStateBits() & NS_STATE_BOX_WRAPS_KIDS_IN_BLOCK) &&
       aItems.AnyItemsNeedBlockParent()) {
     RecreateFramesForContent(aFrame->GetContent(), true);
     return true;
   }
   nsIFrame* nextSibling = ::GetInsertNextSibling(aFrame, aPrevSibling);
   // Situation #2 is a flex container frame into which we're inserting new
   // inline non-replaced children, adjacent to an existing anonymous flex item.
   if (aFrame->GetType() == nsGkAtoms::flexContainerFrame) {
     FCItemIterator iter(aItems);
     // Check if we're adding to-be-wrapped content right *after* an existing
     // anonymous flex item (which would need to absorb this content).
     if (aPrevSibling && IsAnonymousFlexItem(aPrevSibling) &&
         iter.item().NeedsAnonFlexItem(aState)) {
       RecreateFramesForContent(aFrame->GetContent(), true);
       return true;
     }
     // Check if we're adding to-be-wrapped content right *before* an existing
     // anonymous flex item (which would need to absorb this content).
     if (nextSibling && IsAnonymousFlexItem(nextSibling)) {
       // Jump to the last entry in the list
       iter.SetToEnd();
       iter.Prev();
       if (iter.item().NeedsAnonFlexItem(aState)) {
         RecreateFramesForContent(aFrame->GetContent(), true);
         return true;
       }
     }
   }
   // Situation #3 is an anonymous flex item that's getting new children who
   // don't want to be wrapped.
   if (IsAnonymousFlexItem(aFrame)) {
     nsIFrame* flexContainerFrame = aFrame->GetParent();
     NS_ABORT_IF_FALSE(flexContainerFrame &&
                       flexContainerFrame->GetType() == nsGkAtoms::flexContainerFrame,
                       "anonymous flex items should only exist as children "
                       "of flex container frames");
     // We need to push a null float containing block to be sure that
     // "NeedsAnonFlexItem" will know we're not honoring floats for this
     // inserted content. (In particular, this is necessary in order for
     // NeedsAnonFlexItem's "GetGeometricParent" call to return the correct
     // result.) We're not honoring floats on this content because it has the
     // _flex container_ as its parent in the content tree.
     nsFrameConstructorSaveState floatSaveState;
     aState.PushFloatContainingBlock(nullptr, floatSaveState);
     FCItemIterator iter(aItems);
     // Skip over things that _do_ need an anonymous flex item, because
     // they're perfectly happy to go here -- they won't cause a reframe.
     if (!iter.SkipItemsThatNeedAnonFlexItem(aState)) {
       // We hit something that _doesn't_ need an anonymous flex item!
       // Rebuild the flex container to bust it out.
       RecreateFramesForContent(flexContainerFrame->GetContent(), true);
       return true;
     }
     // If we get here, then everything in |aItems| needs to be wrapped in
     // an anonymous flex item.  That's where it's already going - good!
   }
   // Situation #4 is a case when table pseudo-frames don't work out right
   ParentType parentType = GetParentType(aFrame);
   // If all the kids want a parent of the type that aFrame is, then we're all
   // set to go.  Indeed, there won't be any table pseudo-frames created between
   // aFrame and the kids, so those won't need to be merged with any table
   // pseudo-frames that might already be kids of aFrame.  If aFrame itself is a
   // table pseudo-frame, then all the kids in this list would have wanted a
   // frame of that type wrapping them anyway, so putting them inside it is ok.
   if (!aItems.AllWantParentType(parentType)) {
     // Don't give up yet.  If parentType is not eTypeBlock and the parent is
     // not a generated content frame, then try filtering whitespace out of the
     // list.
     if (parentType != eTypeBlock && !aFrame->IsGeneratedContentFrame()) {
       // For leading whitespace followed by a kid that wants our parent type,
       // there are four cases:
       // 1) We have a previous sibling which is not a table pseudo.  That means
       //    that previous sibling wanted a (non-block) parent of the type we're
       //    looking at.  Then the whitespace comes between two table-internal
       //    elements, so should be collapsed out.
       // 2) We have a previous sibling which is a table pseudo.  It might have
       //    kids who want this whitespace, so we need to reframe.
       // 3) We have no previous sibling and our parent frame is not a table
       //    pseudo.  That means that we'll be at the beginning of our actual
       //    non-block-type parent, and the whitespace is OK to collapse out.
       //    If something is ever inserted before us, it'll find our own parent
       //    as its parent and if it's something that would care about the
       //    whitespace it'll want a block parent, so it'll trigger a reframe at
       //    that point.
       // 4) We have no previous sibling and our parent frame is a table pseudo.
       //    Need to reframe.
       // All that is predicated on finding the correct previous sibling.  We
       // might have to walk backwards along continuations from aFrame to do so.
       //
       // It's always OK to drop whitespace between any two items that want a
       // parent of type parentType.
       //
       // For trailing whitespace preceded by a kid that wants our parent type,
       // there are four cases:
       // 1) We have a next sibling which is not a table pseudo.  That means
       //    that next sibling wanted a (non-block) parent of the type we're
       //    looking at.  Then the whitespace comes between two table-internal
       //    elements, so should be collapsed out.
       // 2) We have a next sibling which is a table pseudo.  It might have
       //    kids who want this whitespace, so we need to reframe.
       // 3) We have no next sibling and our parent frame is not a table
       //    pseudo.  That means that we'll be at the end of our actual
       //    non-block-type parent, and the whitespace is OK to collapse out.
       //    If something is ever inserted after us, it'll find our own parent
       //    as its parent and if it's something that would care about the
       //    whitespace it'll want a block parent, so it'll trigger a reframe at
       //    that point.
       // 4) We have no next sibling and our parent frame is a table pseudo.
       //    Need to reframe.
       // All that is predicated on finding the correct next sibling.  We might
       // have to walk forward along continuations from aFrame to do so.  That
       // said, in the case when nextSibling is null at this point and aIsAppend
       // is true, we know we're in case 3.  Furthermore, in that case we don't
       // even have to worry about the table pseudo situation; we know our
       // parent is not a table pseudo there.
       FCItemIterator iter(aItems);
       FCItemIterator start(iter);
       do {
         if (iter.SkipItemsWantingParentType(parentType)) {
           break;
         }
         // iter points to an item that wants a different parent.  If it's not
         // whitespace, we're done; no more point scanning the list.
         if (!iter.item().IsWhitespace(aState)) {
           break;
         }
         if (iter == start) {
           // Leading whitespace.  How to handle this depends on our
           // previous sibling and aFrame.  See the long comment above.
           nsIFrame* prevSibling = aPrevSibling;
           if (!prevSibling) {
             // Try to find one after all
             nsIFrame* parentPrevCont = aFrame->GetPrevContinuation();
             while (parentPrevCont) {
               prevSibling = parentPrevCont->GetLastChild(kPrincipalList);
               if (prevSibling) {
                 break;
               }
               parentPrevCont = parentPrevCont->GetPrevContinuation();
             }
           };
           if (prevSibling) {
             if (IsTablePseudo(prevSibling)) {
               // need to reframe
               break;
             }
           } else if (IsTablePseudo(aFrame)) {
             // need to reframe
             break;
           }
         }
         FCItemIterator spaceEndIter(iter);
         // Advance spaceEndIter past any whitespace
         bool trailingSpaces = spaceEndIter.SkipWhitespace(aState);
         bool okToDrop;
         if (trailingSpaces) {
           // Trailing whitespace.  How to handle this depeds on aIsAppend, our
           // next sibling and aFrame.  See the long comment above.
           okToDrop = aIsAppend && !nextSibling;
           if (!okToDrop) {
             if (!nextSibling) {
               // Try to find one after all
               nsIFrame* parentNextCont = aFrame->GetNextContinuation();
               while (parentNextCont) {
                 nextSibling = parentNextCont->GetFirstPrincipalChild();
                 if (nextSibling) {
                   break;
                 }
                 parentNextCont = parentNextCont->GetNextContinuation();
               }
             }
             okToDrop = (nextSibling && !IsTablePseudo(nextSibling)) ||
                        (!nextSibling && !IsTablePseudo(aFrame));
           }
 #ifdef DEBUG
           else {
             NS_ASSERTION(!IsTablePseudo(aFrame), "How did that happen?");
           }
 #endif
         } else {
           okToDrop = (spaceEndIter.item().DesiredParentType() == parentType);
         }
         if (okToDrop) {
           iter.DeleteItemsTo(spaceEndIter);
         } else {
           // We're done: we don't want to drop the whitespace, and it has the
           // wrong parent type.
           break;
         }
         // Now loop, since |iter| points to item right after the whitespace we
         // removed.
       } while (!iter.IsDone());
     }
     // We might be able to figure out some sort of optimizations here, but they
     // would have to depend on having a correct aPrevSibling and a correct next
     // sibling.  For example, we can probably avoid reframing if none of
     // aFrame, aPrevSibling, and next sibling are table pseudo-frames.  But it
     // doesn't seem worth it to worry about that for now, especially since we
     // in fact do not have a reliable aPrevSibling, nor any next sibling, in
     // this method.
     // aItems might have changed, so recheck the parent type thing.  In fact,
     // it might be empty, so recheck that too.
     if (aItems.IsEmpty()) {
       return false;
     }
     if (!aItems.AllWantParentType(parentType)) {
       // Reframing aFrame->GetContent() is good enough, since the content of
       // table pseudo-frames is the ancestor content.
       RecreateFramesForContent(aFrame->GetContent(), true);
       return true;
     }
   }
   // Now we have several cases involving {ib} splits.  Put them all in a
   // do/while with breaks to take us to the "go and reconstruct" code.
   do {
     if (IsInlineFrame(aFrame)) {
       if (aItems.AreAllItemsInline()) {
         // We can just put the kids in.
         return false;
       }
       if (!IsFramePartOfIBSplit(aFrame)) {
         // Need to go ahead and reconstruct.
         break;
       }
       // Now we're adding kids including some blocks to an inline part of an
       // {ib} split.  If we plan to call AppendFrames, and don't have a next
       // sibling for the new frames, and our parent is the last continuation of
       // the last part of the {ib} split, and the same is true of all our
       // ancestor inlines (they have no following continuations and they're the
       // last part of their {ib} splits and we'd be adding to the end for all
       // of them), then AppendFrames will handle things for us.  Bail out in
       // that case.
       if (aIsAppend && IsSafeToAppendToIBSplitInline(aFrame, nextSibling)) {
         return false;
       }
       // Need to reconstruct.
       break;
     }
     // Now we know we have a block parent.  If it's not part of an
     // ib-split, we're all set.
     if (!IsFramePartOfIBSplit(aFrame)) {
       return false;
     }
     // We're adding some kids to a block part of an {ib} split.  If all the
     // kids are blocks, we don't need to reconstruct.
     if (aItems.AreAllItemsBlock()) {
       return false;
     }
     // We might have some inline kids for this block.  Just reconstruct.
     break;
   } while (0);
   // If we don't have a containing block, start with aFrame and look for one.
   if (!aContainingBlock) {
     aContainingBlock = aFrame;
   }
   // To find the right block to reframe, just walk up the tree until we find a
   // frame that is:
   // 1)  Not part of an IB split
   // 2)  Not a pseudo-frame
   // 3)  Not an inline frame
   // We're guaranteed to find one, since nsStyleContext::ApplyStyleFixups
   // enforces that the root is display:none, display:table, or display:block.
   // Note that walking up "too far" is OK in terms of correctness, even if it
   // might be a little inefficient.  This is why we walk out of all
   // pseudo-frames -- telling which ones are or are not OK to walk out of is
   // too hard (and I suspect that we do in fact need to walk out of all of
   // them).
   while (IsFramePartOfIBSplit(aContainingBlock) ||
          aContainingBlock->IsInlineOutside() ||
          aContainingBlock->StyleContext()->GetPseudo()) {
     aContainingBlock = aContainingBlock->GetParent();
     NS_ASSERTION(aContainingBlock,
                  "Must have non-inline, non-ib-split, non-pseudo frame as "
                  "root (or child of root, for a table root)!");
   }
   // Tell parent of the containing block to reformulate the
   // entire block. This is painful and definitely not optimal
   // but it will *always* get the right answer.
   nsIContent *blockContent = aContainingBlock->GetContent();
 #ifdef DEBUG
   if (gNoisyContentUpdates) {
     printf("nsCSSFrameConstructor::WipeContainingBlock: blockContent=%p\n",
            static_cast<void*>(blockContent));
   }
 #endif
   RecreateFramesForContent(blockContent, true);
   return true;
 }
 nsresult
 nsCSSFrameConstructor::ReframeContainingBlock(nsIFrame* aFrame)
 {
 #ifdef DEBUG
   // ReframeContainingBlock is a NASTY routine, it causes terrible performance problems
   // so I want to see when it is happening!  Unfortunately, it is happening way to often because
   // so much content on the web causes block-in-inline frame situations and we handle them
   // very poorly
   if (gNoisyContentUpdates) {
     printf("nsCSSFrameConstructor::ReframeContainingBlock frame=%p\n",
            static_cast<void*>(aFrame));
   }
 #endif
   // XXXbz how exactly would we get here while isReflowing anyway?  Should this
   // whole test be ifdef DEBUG?
   if (mPresShell->IsReflowLocked()) {
     // don't ReframeContainingBlock, this will result in a crash
     // if we remove a tree that's in reflow - see bug 121368 for testcase
     NS_ERROR("Atemptted to nsCSSFrameConstructor::ReframeContainingBlock during a Reflow!!!");
     return NS_OK;
   }
   // Get the first "normal" ancestor of the target frame.
   nsIFrame* containingBlock = GetIBContainingBlockFor(aFrame);
   if (containingBlock) {
     // From here we look for the containing block in case the target
     // frame is already a block (which can happen when an inline frame
     // wraps some of its content in an anonymous block; see
     // ConstructInline)
     // NOTE: We used to get the FloatContainingBlock here, but it was often wrong.
     // GetIBContainingBlock works much better and provides the correct container in all cases
     // so GetFloatContainingBlock(aFrame) has been removed
     // And get the containingBlock's content
     nsCOMPtr<nsIContent> blockContent = containingBlock->GetContent();
     if (blockContent) {
 #ifdef DEBUG
       if (gNoisyContentUpdates) {
         printf("  ==> blockContent=%p\n", static_cast<void*>(blockContent));
       }
 #endif
       return RecreateFramesForContent(blockContent, true);
     }
   }
   // If we get here, we're screwed!
   return RecreateFramesForContent(mPresShell->GetDocument()->GetRootElement(),
 				  true);
 }
 nsresult
 nsCSSFrameConstructor::GenerateChildFrames(nsIFrame* aFrame)
 {
   {
     nsAutoScriptBlocker scriptBlocker;
     BeginUpdate();
     nsFrameItems childItems;
     nsFrameConstructorState state(mPresShell, nullptr, nullptr, nullptr);
     // We don't have a parent frame with a pending binding constructor here,
     // so no need to worry about ordering of the kids' constructors with it.
     // Pass null for the PendingBinding.
     ProcessChildren(state, aFrame->GetContent(), aFrame->StyleContext(),
                     aFrame, false, childItems, false,
                     nullptr);
     aFrame->SetInitialChildList(kPrincipalList, childItems);
     EndUpdate();
   }
 #ifdef ACCESSIBILITY
   nsAccessibilityService* accService = nsIPresShell::AccService();
   if (accService) {
     nsIContent* container = aFrame->GetContent();
     nsIContent* child = container->GetFirstChild();
     if (child) {
       accService->ContentRangeInserted(mPresShell, container, child, nullptr);
     }
   }
 #endif
   // call XBL constructors after the frames are created
   mPresShell->GetDocument()->BindingManager()->ProcessAttachedQueue();
   return NS_OK;
 }
 //////////////////////////////////////////////////////////
 // nsCSSFrameConstructor::FrameConstructionItem methods //
 //////////////////////////////////////////////////////////
 bool
 nsCSSFrameConstructor::
 FrameConstructionItem::IsWhitespace(nsFrameConstructorState& aState) const
 {
   NS_PRECONDITION(aState.mCreatingExtraFrames ||
                   !mContent->GetPrimaryFrame(), "How did that happen?");
   if (!mIsText) {
     return false;
   }
   mContent->SetFlags(NS_CREATE_FRAME_IF_NON_WHITESPACE |
                      NS_REFRAME_IF_WHITESPACE);
   return mContent->TextIsOnlyWhitespace();
 }
 //////////////////////////////////////////////////////////////
 // nsCSSFrameConstructor::FrameConstructionItemList methods //
 //////////////////////////////////////////////////////////////
 void
 nsCSSFrameConstructor::FrameConstructionItemList::
 AdjustCountsForItem(FrameConstructionItem* aItem, int32_t aDelta)
 {
   NS_PRECONDITION(aDelta == 1 || aDelta == -1, "Unexpected delta");
   mItemCount += aDelta;
   if (aItem->mIsAllInline) {
     mInlineCount += aDelta;
   }
   if (aItem->mIsBlock) {
     mBlockCount += aDelta;
   }
   if (aItem->mIsLineParticipant) {
     mLineParticipantCount += aDelta;
   }
   mDesiredParentCounts[aItem->DesiredParentType()] += aDelta;
 }
 ////////////////////////////////////////////////////////////////////////
 // nsCSSFrameConstructor::FrameConstructionItemList::Iterator methods //
 ////////////////////////////////////////////////////////////////////////
 inline bool
 nsCSSFrameConstructor::FrameConstructionItemList::
 Iterator::SkipItemsWantingParentType(ParentType aParentType)
 {
   NS_PRECONDITION(!IsDone(), "Shouldn't be done yet");
   while (item().DesiredParentType() == aParentType) {
     Next();
     if (IsDone()) {
       return true;
     }
   }
   return false;
 }
 bool
 nsCSSFrameConstructor::FrameConstructionItem::
   NeedsAnonFlexItem(const nsFrameConstructorState& aState)
 {
   if (mFCData->mBits & FCDATA_IS_LINE_PARTICIPANT) {
     // This will be an inline non-replaced box.
     return true;
   }
   if (!(mFCData->mBits & FCDATA_DISALLOW_OUT_OF_FLOW) &&
       aState.GetGeometricParent(mStyleContext->StyleDisplay(), nullptr)) {
     // We're abspos or fixedpos, which means we'll spawn a placeholder which
     // we'll need to wrap in an anonymous flex item.  So, we just treat
     // _this_ frame as if _it_ needs to be wrapped in an anonymous flex item,
     // and then when we spawn the placeholder, it'll end up in the right spot.
     return true;
   }
   return false;
 }
 inline bool
 nsCSSFrameConstructor::FrameConstructionItemList::
 Iterator::SkipItemsThatNeedAnonFlexItem(
   const nsFrameConstructorState& aState)
 {
   NS_PRECONDITION(!IsDone(), "Shouldn't be done yet");
   while (item().NeedsAnonFlexItem(aState)) {
     Next();
     if (IsDone()) {
       return true;
     }
   }
   return false;
 }
 inline bool
 nsCSSFrameConstructor::FrameConstructionItemList::
 Iterator::SkipItemsThatDontNeedAnonFlexItem(
   const nsFrameConstructorState& aState)
 {
   NS_PRECONDITION(!IsDone(), "Shouldn't be done yet");
   while (!(item().NeedsAnonFlexItem(aState))) {
     Next();
     if (IsDone()) {
       return true;
     }
   }
   return false;
 }
 inline bool
 nsCSSFrameConstructor::FrameConstructionItemList::
 Iterator::SkipWhitespace(nsFrameConstructorState& aState)
 {
   NS_PRECONDITION(!IsDone(), "Shouldn't be done yet");
   NS_PRECONDITION(item().IsWhitespace(aState), "Not pointing to whitespace?");
   do {
     Next();
     if (IsDone()) {
       return true;
     }
   } while (item().IsWhitespace(aState));
   return false;
 }
 void
 nsCSSFrameConstructor::FrameConstructionItemList::
 Iterator::AppendItemToList(FrameConstructionItemList& aTargetList)
 {
   NS_ASSERTION(&aTargetList != &mList, "Unexpected call");
   NS_PRECONDITION(!IsDone(), "should not be done");
   FrameConstructionItem* item = ToItem(mCurrent);
   Next();
   PR_REMOVE_LINK(item);
   PR_APPEND_LINK(item, &aTargetList.mItems);
   mList.AdjustCountsForItem(item, -1);
   aTargetList.AdjustCountsForItem(item, 1);
 }
 void
 nsCSSFrameConstructor::FrameConstructionItemList::
 Iterator::AppendItemsToList(const Iterator& aEnd,
                             FrameConstructionItemList& aTargetList)
 {
   NS_ASSERTION(&aTargetList != &mList, "Unexpected call");
   NS_PRECONDITION(mEnd == aEnd.mEnd, "end iterator for some other list?");
   // We can't just move our guts to the other list if it already has
   // some information or if we're not moving our entire list.
   if (!AtStart() || !aEnd.IsDone() || !aTargetList.IsEmpty() ||
       !aTargetList.mUndisplayedItems.IsEmpty()) {
     do {
       AppendItemToList(aTargetList);
     } while (*this != aEnd);
     return;
   }
   // move over the list of items
   PR_INSERT_AFTER(&aTargetList.mItems, &mList.mItems);
   // Need to init when we remove to makd ~FrameConstructionItemList work right.
   PR_REMOVE_AND_INIT_LINK(&mList.mItems);
   // Copy over the various counters
   aTargetList.mInlineCount = mList.mInlineCount;
   aTargetList.mBlockCount = mList.mBlockCount;
   aTargetList.mLineParticipantCount = mList.mLineParticipantCount;
   aTargetList.mItemCount = mList.mItemCount;
   memcpy(aTargetList.mDesiredParentCounts, mList.mDesiredParentCounts,
          sizeof(aTargetList.mDesiredParentCounts));
   // Swap out undisplayed item arrays, before we nuke the array on our end
   aTargetList.mUndisplayedItems.SwapElements(mList.mUndisplayedItems);
   // reset mList
   mList.~FrameConstructionItemList();
   new (&mList) FrameConstructionItemList();
   // Point ourselves to aEnd, as advertised
   mCurrent = mEnd = &mList.mItems;
   NS_POSTCONDITION(*this == aEnd, "How did that happen?");
 }
 void
 nsCSSFrameConstructor::FrameConstructionItemList::
 Iterator::InsertItem(FrameConstructionItem* aItem)
 {
   // Just insert the item before us.  There's no magic here.
   PR_INSERT_BEFORE(aItem, mCurrent);
   mList.AdjustCountsForItem(aItem, 1);
   NS_POSTCONDITION(PR_NEXT_LINK(aItem) == mCurrent, "How did that happen?");
 }
 void
 nsCSSFrameConstructor::FrameConstructionItemList::
 Iterator::DeleteItemsTo(const Iterator& aEnd)
 {
   NS_PRECONDITION(mEnd == aEnd.mEnd, "end iterator for some other list?");
   NS_PRECONDITION(*this != aEnd, "Shouldn't be at aEnd yet");
   do {
     NS_ASSERTION(!IsDone(), "Ran off end of list?");
     FrameConstructionItem* item = ToItem(mCurrent);
     Next();
     PR_REMOVE_LINK(item);
     mList.AdjustCountsForItem(item, -1);
     delete item;
   } while (*this != aEnd);
 }

The Tor Browser / annotate

layout/base/nsCSSFrameConstructor.cpp@b8a032363ba2 (annotated)

layout/base/nsCSSFrameConstructor.cpp