The Tor Browser: layout/base/nsIPresShell.h@b8a032363ba2 (annotated)

layout/base/nsIPresShell.h@b8a032363ba2 (annotated)

layout/base/nsIPresShell.h

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 -*-
  * 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/.
  *
  * This Original Code has been modified by IBM Corporation.
  * Modifications made by IBM described herein are
  * Copyright (c) International Business Machines
  * Corporation, 2000
  *
  * Modifications to Mozilla code or documentation
  * identified per MPL Section 3.3
  *
  * Date         Modified by     Description of modification
  * 05/03/2000   IBM Corp.       Observer related defines for reflow
  */
 /* a presentation of a document, part 2 */
 #ifndef nsIPresShell_h___
 #define nsIPresShell_h___
 #include "mozilla/EventForwards.h"
 #include "mozilla/MemoryReporting.h"
 #include "mozilla/WeakPtr.h"
 #include "gfxPoint.h"
 #include "nsTHashtable.h"
 #include "nsHashKeys.h"
 #include "nsISupports.h"
 #include "nsQueryFrame.h"
 #include "nsCoord.h"
 #include "nsColor.h"
 #include "nsCompatibility.h"
 #include "nsFrameManagerBase.h"
 #include "mozFlushType.h"
 #include "nsWeakReference.h"
 #include <stdio.h> // for FILE definition
 #include "nsChangeHint.h"
 #include "nsRefPtrHashtable.h"
 #include "nsClassHashtable.h"
 #include "nsPresArena.h"
 #include "nsIImageLoadingContent.h"
 #include "nsMargin.h"
 #include "nsFrameState.h"
 class nsIContent;
 class nsDocShell;
 class nsIDocument;
 class nsIFrame;
 class nsPresContext;
 class nsStyleSet;
 class nsViewManager;
 class nsView;
 class nsRenderingContext;
 class nsIPageSequenceFrame;
 class nsAString;
 class nsCaret;
 class nsFrameSelection;
 class nsFrameManager;
 class nsILayoutHistoryState;
 class nsIReflowCallback;
 class nsIDOMNode;
 class nsIntRegion;
 class nsIStyleSheet;
 class nsCSSFrameConstructor;
 class nsISelection;
 template<class E> class nsCOMArray;
 class nsWeakFrame;
 class nsIScrollableFrame;
 class gfxContext;
 class nsIDOMEvent;
 class nsDisplayList;
 class nsDisplayListBuilder;
 class nsPIDOMWindow;
 struct nsPoint;
 struct nsIntPoint;
 struct nsIntRect;
 struct nsRect;
 class nsRegion;
 class nsRefreshDriver;
 class nsARefreshObserver;
 class nsAPostRefreshObserver;
 #ifdef ACCESSIBILITY
 class nsAccessibilityService;
 namespace mozilla {
 namespace a11y {
 class DocAccessible;
 } // namespace a11y
 } // namespace mozilla
 #endif
 class nsIWidget;
 struct nsArenaMemoryStats;
 typedef short SelectionType;
 namespace mozilla {
 class EventStates;
 namespace dom {
 class Element;
 class Touch;
 class Selection;
 class ShadowRoot;
 } // namespace dom
 namespace layers {
 class LayerManager;
 } // namespace layers
 namespace gfx {
 class SourceSurface;
 } // namespace gfx
 } // namespace mozilla
 // Flags to pass to SetCapturingContent
 //
 // when assigning capture, ignore whether capture is allowed or not
 #define CAPTURE_IGNOREALLOWED 1
 // true if events should be targeted at the capturing content or its children
 #define CAPTURE_RETARGETTOELEMENT 2
 // true if the current capture wants drags to be prevented
 #define CAPTURE_PREVENTDRAG 4
 // true when the mouse is pointer locked, and events are sent to locked element
 #define CAPTURE_POINTERLOCK 8
 typedef struct CapturingContentInfo {
   // capture should only be allowed during a mousedown event
   bool mAllowed;
   bool mPointerLock;
   bool mRetargetToElement;
   bool mPreventDrag;
   nsIContent* mContent;
 } CapturingContentInfo;
 //61e60df7-128a-4cdd-a684-5f0bd2ceb61f
 #define NS_IPRESSHELL_IID \
 { 0x61e60df7, 0x128a, 0x4cdd, \
   {0xa6, 0x84, 0x5f, 0x0b, 0xd2, 0xce, 0xb6, 0x1f}}
 // debug VerifyReflow flags
 #define VERIFY_REFLOW_ON                    0x01
 #define VERIFY_REFLOW_NOISY                 0x02
 #define VERIFY_REFLOW_ALL                   0x04
 #define VERIFY_REFLOW_DUMP_COMMANDS         0x08
 #define VERIFY_REFLOW_NOISY_RC              0x10
 #define VERIFY_REFLOW_REALLY_NOISY_RC       0x20
 #define VERIFY_REFLOW_DURING_RESIZE_REFLOW  0x40
 #undef NOISY_INTERRUPTIBLE_REFLOW
 enum nsRectVisibility {
   nsRectVisibility_kVisible,
   nsRectVisibility_kAboveViewport,
   nsRectVisibility_kBelowViewport,
   nsRectVisibility_kLeftOfViewport,
   nsRectVisibility_kRightOfViewport
 };
 /**
  * Presentation shell interface. Presentation shells are the
  * controlling point for managing the presentation of a document. The
  * presentation shell holds a live reference to the document, the
  * presentation context, the style manager, the style set and the root
  * frame. <p>
  *
  * When this object is Release'd, it will release the document, the
  * presentation context, the style manager, the style set and the root
  * frame.
  */
 class nsIPresShell : public nsISupports
 {
 public:
   NS_DECLARE_STATIC_IID_ACCESSOR(NS_IPRESSHELL_IID)
 protected:
   typedef mozilla::layers::LayerManager LayerManager;
   typedef mozilla::gfx::SourceSurface SourceSurface;
   enum eRenderFlag {
     STATE_IGNORING_VIEWPORT_SCROLLING = 0x1,
     STATE_DRAWWINDOW_NOT_FLUSHING = 0x2
   };
   typedef uint8_t RenderFlags; // for storing the above flags
 public:
   /**
    * All callers are responsible for calling |Destroy| after calling
    * |EndObservingDocument|.  It needs to be separate only because form
    * controls incorrectly store their data in the frames rather than the
    * content model and printing calls |EndObservingDocument| multiple
    * times to make form controls behave nicely when printed.
    */
   virtual NS_HIDDEN_(void) Destroy() = 0;
   bool IsDestroying() { return mIsDestroying; }
   /**
    * Make a one-way transition into a "zombie" state.  In this state,
    * no reflow is done, no painting is done, and no refresh driver
    * ticks are processed.  This is a dangerous state: it can leave
    * areas of the composition target unpainted if callers aren't
    * careful.  (Don't let your zombie presshell out of the shed.)
    *
    * This is used in cases where a presshell is created for reasons
    * other than reflow/painting.
    */
   virtual NS_HIDDEN_(void) MakeZombie() = 0;
   /**
    * All frames owned by the shell are allocated from an arena.  They
    * are also recycled using free lists.  Separate free lists are
    * maintained for each frame type (aID), which must always correspond
    * to the same aSize value.  AllocateFrame returns zero-filled memory.
    * AllocateFrame is infallible and will abort on out-of-memory.
    */
   void* AllocateFrame(nsQueryFrame::FrameIID aID, size_t aSize)
   {
 #ifdef DEBUG
     mPresArenaAllocCount++;
 #endif
     void* result = mFrameArena.AllocateByFrameID(aID, aSize);
     memset(result, 0, aSize);
     return result;
   }
   void FreeFrame(nsQueryFrame::FrameIID aID, void* aPtr)
   {
 #ifdef DEBUG
     mPresArenaAllocCount--;
 #endif
     if (!mIsDestroying)
       mFrameArena.FreeByFrameID(aID, aPtr);
   }
   /**
    * This is for allocating other types of objects (not frames).  Separate free
    * lists are maintained for each type (aID), which must always correspond to
    * the same aSize value.  AllocateByObjectID returns zero-filled memory.
    * AllocateByObjectID is infallible and will abort on out-of-memory.
    */
   void* AllocateByObjectID(nsPresArena::ObjectID aID, size_t aSize)
   {
 #ifdef DEBUG
     mPresArenaAllocCount++;
 #endif
     void* result = mFrameArena.AllocateByObjectID(aID, aSize);
     memset(result, 0, aSize);
     return result;
   }
   void FreeByObjectID(nsPresArena::ObjectID aID, void* aPtr)
   {
 #ifdef DEBUG
     mPresArenaAllocCount--;
 #endif
     if (!mIsDestroying)
       mFrameArena.FreeByObjectID(aID, aPtr);
   }
   /**
    * Other objects closely related to the frame tree that are allocated
    * from a separate set of per-size free lists.  Note that different types
    * of objects that has the same size are allocated from the same list.
    * AllocateMisc does *not* clear the memory that it returns.
    * AllocateMisc is infallible and will abort on out-of-memory.
    *
    * @deprecated use AllocateByObjectID/FreeByObjectID instead
    */
   void* AllocateMisc(size_t aSize)
   {
 #ifdef DEBUG
     mPresArenaAllocCount++;
 #endif
     return mFrameArena.AllocateBySize(aSize);
   }
   void FreeMisc(size_t aSize, void* aPtr)
   {
 #ifdef DEBUG
     mPresArenaAllocCount--;
 #endif
     if (!mIsDestroying)
       mFrameArena.FreeBySize(aSize, aPtr);
   }
   nsIDocument* GetDocument() const { return mDocument; }
   nsPresContext* GetPresContext() const { return mPresContext; }
   nsViewManager* GetViewManager() const { return mViewManager; }
 #ifdef ACCESSIBILITY
   /**
    * Return the document accessible for this pres shell if there is one.
    */
   mozilla::a11y::DocAccessible* GetDocAccessible() const
   {
     return mDocAccessible;
   }
   /**
    * Set the document accessible for this pres shell.
    */
   void SetDocAccessible(mozilla::a11y::DocAccessible* aDocAccessible)
   {
     mDocAccessible = aDocAccessible;
   }
 #endif
 #ifdef MOZILLA_INTERNAL_API
   nsStyleSet* StyleSet() const { return mStyleSet; }
   nsCSSFrameConstructor* FrameConstructor() const { return mFrameConstructor; }
   nsFrameManager* FrameManager() const {
     // reinterpret_cast is valid since nsFrameManager does not add
     // any members over nsFrameManagerBase.
     return reinterpret_cast<nsFrameManager*>
                            (const_cast<nsIPresShell*>(this)->mFrameManager);
   }
 #endif
   /* Enable/disable author style level. Disabling author style disables the entire
    * author level of the cascade, including the HTML preshint level.
    */
   // XXX these could easily be inlined, but there is a circular #include
   // problem with nsStyleSet.
   NS_HIDDEN_(void) SetAuthorStyleDisabled(bool aDisabled);
   NS_HIDDEN_(bool) GetAuthorStyleDisabled() const;
   /*
    * Called when stylesheets are added/removed/enabled/disabled to rebuild
    * all style data for a given pres shell without necessarily reconstructing
    * all of the frames.  This will not reconstruct style synchronously; if
    * you need to do that, call FlushPendingNotifications to flush out style
    * reresolves.
    * // XXXbz why do we have this on the interface anyway?  The only consumer
    * is calling AddOverrideStyleSheet/RemoveOverrideStyleSheet, and I think
    * those should just handle reconstructing style data...
    */
   virtual NS_HIDDEN_(void) ReconstructStyleDataExternal();
   NS_HIDDEN_(void) ReconstructStyleDataInternal();
 #ifdef MOZILLA_INTERNAL_API
   void ReconstructStyleData() { ReconstructStyleDataInternal(); }
 #else
   void ReconstructStyleData() { ReconstructStyleDataExternal(); }
 #endif
   /** Setup all style rules required to implement preferences
    * - used for background/text/link colors and link underlining
    *    may be extended for any prefs that are implemented via style rules
    * - aForceReflow argument is used to force a full reframe to make the rules show
    *   (only used when the current page needs to reflect changed pref rules)
    *
    * - initially created for bugs 31816, 20760, 22963
    */
   virtual NS_HIDDEN_(nsresult) SetPreferenceStyleRules(bool aForceReflow) = 0;
   /**
    * FrameSelection will return the Frame based selection API.
    * You cannot go back and forth anymore with QI between nsIDOM sel and
    * nsIFrame sel.
    */
   already_AddRefed<nsFrameSelection> FrameSelection();
   /**
    * ConstFrameSelection returns an object which methods are safe to use for
    * example in nsIFrame code.
    */
   const nsFrameSelection* ConstFrameSelection() const { return mSelection; }
   // Make shell be a document observer.  If called after Destroy() has
   // been called on the shell, this will be ignored.
   virtual NS_HIDDEN_(void) BeginObservingDocument() = 0;
   // Make shell stop being a document observer
   virtual NS_HIDDEN_(void) EndObservingDocument() = 0;
   /**
    * Return whether Initialize() was previously called.
    */
   bool DidInitialize() const { return mDidInitialize; }
   /**
    * Perform initialization. Constructs the frame for the root content
    * object and then enqueues a reflow of the frame model into the
    * specified width and height.
    *
    * The coordinates for aWidth and aHeight must be in standard nscoords.
    *
    * Callers of this method must hold a reference to this shell that
    * is guaranteed to survive through arbitrary script execution.
    * Calling Initialize can execute arbitrary script.
    */
   virtual NS_HIDDEN_(nsresult) Initialize(nscoord aWidth, nscoord aHeight) = 0;
   /**
    * Reflow the frame model into a new width and height.  The
    * coordinates for aWidth and aHeight must be in standard nscoord's.
    */
   virtual NS_HIDDEN_(nsresult) ResizeReflow(nscoord aWidth, nscoord aHeight) = 0;
   /**
    * Reflow, and also change presshell state so as to only permit
    * reflowing off calls to ResizeReflowOverride() in the future.
    * ResizeReflow() calls are ignored after ResizeReflowOverride().
    */
   virtual NS_HIDDEN_(nsresult) ResizeReflowOverride(nscoord aWidth, nscoord aHeight) = 0;
   /**
    * Returns true if ResizeReflowOverride has been called.
    */
   virtual bool GetIsViewportOverridden() = 0;
   /**
    * Return true if the presshell expects layout flush.
    */
   virtual bool IsLayoutFlushObserver() = 0;
   /**
    * Called when document load completes.
    */
   virtual NS_HIDDEN_(void) LoadComplete() = 0;
   /**
    * This calls through to the frame manager to get the root frame.
    */
   virtual NS_HIDDEN_(nsIFrame*) GetRootFrameExternal() const;
   nsIFrame* GetRootFrame() const {
 #ifdef MOZILLA_INTERNAL_API
     return mFrameManager->GetRootFrame();
 #else
     return GetRootFrameExternal();
 #endif
   }
   /*
    * Get root scroll frame from FrameManager()->GetRootFrame().
    */
   nsIFrame* GetRootScrollFrame() const;
   /*
    * The same as GetRootScrollFrame, but returns an nsIScrollableFrame
    */
   nsIScrollableFrame* GetRootScrollFrameAsScrollable() const;
   /*
    * The same as GetRootScrollFrame, but returns an nsIScrollableFrame.
    * Can be called by code not linked into gklayout.
    */
   virtual nsIScrollableFrame* GetRootScrollFrameAsScrollableExternal() const;
   /*
    * Gets nearest scrollable frame from current focused content or DOM
    * selection if there is no focused content. The frame is scrollable with
    * overflow:scroll or overflow:auto in some direction when aDirection is
    * eEither.  Otherwise, this returns a nearest frame that is scrollable in
    * the specified direction.
    */
   enum ScrollDirection { eHorizontal, eVertical, eEither };
   nsIScrollableFrame* GetFrameToScrollAsScrollable(ScrollDirection aDirection);
   /**
    * Returns the page sequence frame associated with the frame hierarchy.
    * Returns nullptr if not a paginated view.
    */
   virtual NS_HIDDEN_(nsIPageSequenceFrame*) GetPageSequenceFrame() const = 0;
   /**
    * Gets the real primary frame associated with the content object.
    *
    * In the case of absolutely positioned elements and floated elements,
    * the real primary frame is the frame that is out of the flow and not the
    * placeholder frame.
    */
   virtual NS_HIDDEN_(nsIFrame*) GetRealPrimaryFrameFor(nsIContent* aContent) const = 0;
   /**
    * Gets the placeholder frame associated with the specified frame. This is
    * a helper frame that forwards the request to the frame manager.
    */
   virtual NS_HIDDEN_(nsIFrame*) GetPlaceholderFrameFor(nsIFrame* aFrame) const = 0;
   /**
    * Tell the pres shell that a frame needs to be marked dirty and needs
    * Reflow.  It's OK if this is an ancestor of the frame needing reflow as
    * long as the ancestor chain between them doesn't cross a reflow root.
    *
    * The bit to add should be NS_FRAME_IS_DIRTY, NS_FRAME_HAS_DIRTY_CHILDREN
    * or nsFrameState(0); passing 0 means that dirty bits won't be set on the
    * frame or its ancestors/descendants, but that intrinsic widths will still
    * be marked dirty.  Passing aIntrinsicDirty = eResize and aBitToAdd = 0
    * would result in no work being done, so don't do that.
    */
   enum IntrinsicDirty {
     // XXXldb eResize should be renamed
     eResize,     // don't mark any intrinsic widths dirty
     eTreeChange, // mark intrinsic widths dirty on aFrame and its ancestors
     eStyleChange // Do eTreeChange, plus all of aFrame's descendants
   };
   virtual NS_HIDDEN_(void) FrameNeedsReflow(nsIFrame *aFrame,
                                             IntrinsicDirty aIntrinsicDirty,
                                             nsFrameState aBitToAdd) = 0;
   /**
    * Calls FrameNeedsReflow on all fixed position children of the root frame.
    */
   virtual void MarkFixedFramesForReflow(IntrinsicDirty aIntrinsicDirty);
   /**
    * Tell the presshell that the given frame's reflow was interrupted.  This
    * will mark as having dirty children a path from the given frame (inclusive)
    * to the nearest ancestor with a dirty subtree, or to the reflow root
    * currently being reflowed if no such ancestor exists (inclusive).  This is
    * to be done immediately after reflow of the current reflow root completes.
    * This method must only be called during reflow, and the frame it's being
    * called on must be in the process of being reflowed when it's called.  This
    * method doesn't mark any intrinsic widths dirty and doesn't add any bits
    * other than NS_FRAME_HAS_DIRTY_CHILDREN.
    */
   virtual NS_HIDDEN_(void) FrameNeedsToContinueReflow(nsIFrame *aFrame) = 0;
   virtual NS_HIDDEN_(void) CancelAllPendingReflows() = 0;
   /**
    * Recreates the frames for a node
    */
   virtual NS_HIDDEN_(nsresult) RecreateFramesFor(nsIContent* aContent) = 0;
   void PostRecreateFramesFor(mozilla::dom::Element* aElement);
   void RestyleForAnimation(mozilla::dom::Element* aElement,
                            nsRestyleHint aHint);
   // ShadowRoot has APIs that can change styles so we only
   // want to restyle elements in the ShadowRoot and not the whole
   // document.
   virtual void RestyleShadowRoot(mozilla::dom::ShadowRoot* aShadowRoot) = 0;
   /**
    * Determine if it is safe to flush all pending notifications
    * @param aIsSafeToFlush true if it is safe, false otherwise.
    *
    */
   virtual NS_HIDDEN_(bool) IsSafeToFlush() const = 0;
   /**
    * Flush pending notifications of the type specified.  This method
    * will not affect the content model; it'll just affect style and
    * frames. Callers that actually want up-to-date presentation (other
    * than the document itself) should probably be calling
    * nsIDocument::FlushPendingNotifications.
    *
    * @param aType the type of notifications to flush
    */
   virtual NS_HIDDEN_(void) FlushPendingNotifications(mozFlushType aType) = 0;
   virtual NS_HIDDEN_(void) FlushPendingNotifications(mozilla::ChangesToFlush aType) = 0;
   /**
    * Callbacks will be called even if reflow itself fails for
    * some reason.
    */
   virtual NS_HIDDEN_(nsresult) PostReflowCallback(nsIReflowCallback* aCallback) = 0;
   virtual NS_HIDDEN_(void) CancelReflowCallback(nsIReflowCallback* aCallback) = 0;
   virtual NS_HIDDEN_(void) ClearFrameRefs(nsIFrame* aFrame) = 0;
   /**
    * Get a reference rendering context. This is a context that should not
    * be rendered to, but is suitable for measuring text and performing
    * other non-rendering operations. Guaranteed to return non-null.
    */
   virtual already_AddRefed<nsRenderingContext> CreateReferenceRenderingContext() = 0;
   /**
    * Informs the pres shell that the document is now at the anchor with
    * the given name.  If |aScroll| is true, scrolls the view of the
    * document so that the anchor with the specified name is displayed at
    * the top of the window.  If |aAnchorName| is empty, then this informs
    * the pres shell that there is no current target, and |aScroll| must
    * be false.
    */
   virtual NS_HIDDEN_(nsresult) GoToAnchor(const nsAString& aAnchorName, bool aScroll) = 0;
   /**
    * Tells the presshell to scroll again to the last anchor scrolled to by
    * GoToAnchor, if any. This scroll only happens if the scroll
    * position has not changed since the last GoToAnchor. This is called
    * by nsDocumentViewer::LoadComplete. This clears the last anchor
    * scrolled to by GoToAnchor (we don't want to keep it alive if it's
    * removed from the DOM), so don't call this more than once.
    */
   virtual NS_HIDDEN_(nsresult) ScrollToAnchor() = 0;
   enum {
     SCROLL_TOP     = 0,
     SCROLL_BOTTOM  = 100,
     SCROLL_LEFT    = 0,
     SCROLL_RIGHT   = 100,
     SCROLL_CENTER  = 50,
     SCROLL_MINIMUM = -1
   };
   enum WhenToScroll {
     SCROLL_ALWAYS,
     SCROLL_IF_NOT_VISIBLE,
     SCROLL_IF_NOT_FULLY_VISIBLE
   };
   typedef struct ScrollAxis {
     int16_t mWhereToScroll;
     WhenToScroll mWhenToScroll : 8;
     bool mOnlyIfPerceivedScrollableDirection : 1;
   /**
    * @param aWhere: Either a percentage or a special value.
    *                nsIPresShell defines:
    *                * (Default) SCROLL_MINIMUM = -1: The visible area is
    *                scrolled to show the entire frame. If the frame is too
    *                large, the top and left edges are given precedence.
    *                * SCROLL_TOP = 0: The frame's upper edge is aligned with the
    *                top edge of the visible area.
    *                * SCROLL_BOTTOM = 100: The frame's bottom edge is aligned
    *                with the bottom edge of the visible area.
    *                * SCROLL_LEFT = 0: The frame's left edge is aligned with the
    *                left edge of the visible area.
    *                * SCROLL_RIGHT = 100: The frame's right edge is aligned with
    *                the right edge of the visible area.
    *                * SCROLL_CENTER = 50: The frame is centered along the axis
    *                the ScrollAxis is used for.
    *
    *                Other values are treated as a percentage, and the point
    *                "percent" down the frame is placed at the point "percent"
    *                down the visible area.
    * @param aWhen:
    *                * (Default) SCROLL_IF_NOT_FULLY_VISIBLE: Move the frame only
    *                if it is not fully visible (including if it's not visible
    *                at all). Note that in this case if the frame is too large to
    *                fit in view, it will only be scrolled if more of it can fit
    *                than is already in view.
    *                * SCROLL_IF_NOT_VISIBLE: Move the frame only if none of it
    *                is visible.
    *                * SCROLL_ALWAYS: Move the frame regardless of its current
    *                visibility.
    * @param aOnlyIfPerceivedScrollableDirection:
    *                If the direction is not a perceived scrollable direction (i.e.
    *                no scrollbar showing and less than one device pixel of
    *                scrollable distance), don't scroll. Defaults to false.
    */
     ScrollAxis(int16_t aWhere = SCROLL_MINIMUM,
                WhenToScroll aWhen = SCROLL_IF_NOT_FULLY_VISIBLE,
                bool aOnlyIfPerceivedScrollableDirection = false) :
       mWhereToScroll(aWhere), mWhenToScroll(aWhen),
       mOnlyIfPerceivedScrollableDirection(aOnlyIfPerceivedScrollableDirection)
     {}
   } ScrollAxis;
   /**
    * Scrolls the view of the document so that the primary frame of the content
    * is displayed in the window. Layout is flushed before scrolling.
    *
    * @param aContent  The content object of which primary frame should be
    *                  scrolled into view.
    * @param aVertical How to align the frame vertically and when to do so.
    *                  This is a ScrollAxis of Where and When.
    * @param aHorizontal How to align the frame horizontally and when to do so.
    *                  This is a ScrollAxis of Where and When.
    * @param aFlags    If SCROLL_FIRST_ANCESTOR_ONLY is set, only the nearest
    *                  scrollable ancestor is scrolled, otherwise all
    *                  scrollable ancestors may be scrolled if necessary.
    *                  If SCROLL_OVERFLOW_HIDDEN is set then we may scroll in a
    *                  direction even if overflow:hidden is specified in that
    *                  direction; otherwise we will not scroll in that direction
    *                  when overflow:hidden is set for that direction.
    *                  If SCROLL_NO_PARENT_FRAMES is set then we only scroll
    *                  nodes in this document, not in any parent documents which
    *                  contain this document in a iframe or the like.
    */
   virtual NS_HIDDEN_(nsresult) ScrollContentIntoView(nsIContent* aContent,
                                                      ScrollAxis  aVertical,
                                                      ScrollAxis  aHorizontal,
                                                      uint32_t    aFlags) = 0;
   enum {
     SCROLL_FIRST_ANCESTOR_ONLY = 0x01,
     SCROLL_OVERFLOW_HIDDEN = 0x02,
     SCROLL_NO_PARENT_FRAMES = 0x04
   };
   /**
    * Scrolls the view of the document so that the given area of a frame
    * is visible, if possible. Layout is not flushed before scrolling.
    *
    * @param aRect relative to aFrame
    * @param aVertical see ScrollContentIntoView and ScrollAxis
    * @param aHorizontal see ScrollContentIntoView and ScrollAxis
    * @param aFlags if SCROLL_FIRST_ANCESTOR_ONLY is set, only the
    * nearest scrollable ancestor is scrolled, otherwise all
    * scrollable ancestors may be scrolled if necessary
    * if SCROLL_OVERFLOW_HIDDEN is set then we may scroll in a direction
    * even if overflow:hidden is specified in that direction; otherwise
    * we will not scroll in that direction when overflow:hidden is
    * set for that direction
    * If SCROLL_NO_PARENT_FRAMES is set then we only scroll
    * nodes in this document, not in any parent documents which
    * contain this document in a iframe or the like.
    * @return true if any scrolling happened, false if no scrolling happened
    */
   virtual bool ScrollFrameRectIntoView(nsIFrame*     aFrame,
                                        const nsRect& aRect,
                                        ScrollAxis    aVertical,
                                        ScrollAxis    aHorizontal,
                                        uint32_t      aFlags) = 0;
   /**
    * Determine if a rectangle specified in the frame's coordinate system
    * intersects the viewport "enough" to be considered visible.
    * @param aFrame frame that aRect coordinates are specified relative to
    * @param aRect rectangle in twips to test for visibility
    * @param aMinTwips is the minimum distance in from the edge of the viewport
    *                  that an object must be to be counted visible
    * @return nsRectVisibility_kVisible if the rect is visible
    *         nsRectVisibility_kAboveViewport
    *         nsRectVisibility_kBelowViewport
    *         nsRectVisibility_kLeftOfViewport
    *         nsRectVisibility_kRightOfViewport rectangle is outside the viewport
    *         in the specified direction
    */
   virtual nsRectVisibility GetRectVisibility(nsIFrame *aFrame,
                                              const nsRect &aRect,
                                              nscoord aMinTwips) const = 0;
   /**
    * Suppress notification of the frame manager that frames are
    * being destroyed.
    */
   virtual NS_HIDDEN_(void) SetIgnoreFrameDestruction(bool aIgnore) = 0;
   /**
    * Notification sent by a frame informing the pres shell that it is about to
    * be destroyed.
    * This allows any outstanding references to the frame to be cleaned up
    */
   virtual NS_HIDDEN_(void) NotifyDestroyingFrame(nsIFrame* aFrame) = 0;
   /**
    * Get the caret, if it exists. AddRefs it.
    */
   virtual NS_HIDDEN_(already_AddRefed<nsCaret>) GetCaret() const = 0;
   /**
    * Invalidate the caret's current position if it's outside of its frame's
    * boundaries. This function is useful if you're batching selection
    * notifications and might remove the caret's frame out from under it.
    */
   virtual NS_HIDDEN_(void) MaybeInvalidateCaretPosition() = 0;
   /**
    * Set the current caret to a new caret. To undo this, call RestoreCaret.
    */
   virtual void SetCaret(nsCaret *aNewCaret) = 0;
   /**
    * Restore the caret to the original caret that this pres shell was created
    * with.
    */
   virtual void RestoreCaret() = 0;
   /**
    * Should the images have borders etc.  Actual visual effects are determined
    * by the frames.  Visual effects may not effect layout, only display.
    * Takes effect on next repaint, does not force a repaint itself.
    *
    * @param aInEnable  if true, visual selection effects are enabled
    *                   if false visual selection effects are disabled
    */
   NS_IMETHOD SetSelectionFlags(int16_t aInEnable) = 0;
   /**
     * Gets the current state of non text selection effects
     * @return   current state of non text selection,
     *           as set by SetDisplayNonTextSelection
     */
   int16_t GetSelectionFlags() const { return mSelectionFlags; }
   virtual mozilla::dom::Selection* GetCurrentSelection(SelectionType aType) = 0;
   /**
     * Interface to dispatch events via the presshell
     * @note The caller must have a strong reference to the PresShell.
     */
   virtual NS_HIDDEN_(nsresult) HandleEventWithTarget(
                                  mozilla::WidgetEvent* aEvent,
                                  nsIFrame* aFrame,
                                  nsIContent* aContent,
                                  nsEventStatus* aStatus) = 0;
   /**
    * Dispatch event to content only (NOT full processing)
    * @note The caller must have a strong reference to the PresShell.
    */
   virtual NS_HIDDEN_(nsresult) HandleDOMEventWithTarget(
                                  nsIContent* aTargetContent,
                                  mozilla::WidgetEvent* aEvent,
                                  nsEventStatus* aStatus) = 0;
   /**
    * Dispatch event to content only (NOT full processing)
    * @note The caller must have a strong reference to the PresShell.
    */
   virtual NS_HIDDEN_(nsresult) HandleDOMEventWithTarget(nsIContent* aTargetContent,
                                                         nsIDOMEvent* aEvent,
                                                         nsEventStatus* aStatus) = 0;
   /**
     * Gets the current target event frame from the PresShell
     */
   virtual NS_HIDDEN_(nsIFrame*) GetEventTargetFrame() = 0;
   /**
     * Gets the current target event frame from the PresShell
     */
   virtual NS_HIDDEN_(already_AddRefed<nsIContent>) GetEventTargetContent(
                                                      mozilla::WidgetEvent* aEvent) = 0;
   /**
    * Get and set the history state for the current document
    */
   virtual NS_HIDDEN_(nsresult) CaptureHistoryState(nsILayoutHistoryState** aLayoutHistoryState) = 0;
   /**
    * Determine if reflow is currently locked
    * returns true if reflow is locked, false otherwise
    */
   bool IsReflowLocked() const { return mIsReflowing; }
   /**
    * Called to find out if painting is suppressed for this presshell.  If it is suppressd,
    * we don't allow the painting of any layer but the background, and we don't
    * recur into our children.
    */
   bool IsPaintingSuppressed() const { return mPaintingSuppressed; }
   /**
    * Pause painting by freezing the refresh driver of this and all parent
    * presentations. This may not have the desired effect if this pres shell
    * has its own refresh driver.
    */
   virtual void PausePainting() = 0;
   /**
    * Resume painting by thawing the refresh driver of this and all parent
    * presentations. This may not have the desired effect if this pres shell
    * has its own refresh driver.
    */
   virtual void ResumePainting() = 0;
   /**
    * Unsuppress painting.
    */
   virtual NS_HIDDEN_(void) UnsuppressPainting() = 0;
   /**
    * Called to disable nsITheme support in a specific presshell.
    */
   void DisableThemeSupport()
   {
     // Doesn't have to be dynamic.  Just set the bool.
     mIsThemeSupportDisabled = true;
   }
   /**
    * Indicates whether theme support is enabled.
    */
   bool IsThemeSupportEnabled() const { return !mIsThemeSupportDisabled; }
   /**
    * Get the set of agent style sheets for this presentation
    */
   virtual nsresult GetAgentStyleSheets(nsCOMArray<nsIStyleSheet>& aSheets) = 0;
   /**
    * Replace the set of agent style sheets
    */
   virtual nsresult SetAgentStyleSheets(const nsCOMArray<nsIStyleSheet>& aSheets) = 0;
   /**
    * Add an override style sheet for this presentation
    */
   virtual nsresult AddOverrideStyleSheet(nsIStyleSheet *aSheet) = 0;
   /**
    * Remove an override style sheet
    */
   virtual nsresult RemoveOverrideStyleSheet(nsIStyleSheet *aSheet) = 0;
   /**
    * Reconstruct frames for all elements in the document
    */
   virtual nsresult ReconstructFrames() = 0;
   /**
    * Notify that a content node's state has changed
    */
   virtual void ContentStateChanged(nsIDocument* aDocument,
                                    nsIContent* aContent,
                                    mozilla::EventStates aStateMask) = 0;
   /**
    * See if reflow verification is enabled. To enable reflow verification add
    * "verifyreflow:1" to your NSPR_LOG_MODULES environment variable
    * (any non-zero debug level will work). Or, call SetVerifyReflowEnable
    * with true.
    */
   static bool GetVerifyReflowEnable();
   /**
    * Set the verify-reflow enable flag.
    */
   static void SetVerifyReflowEnable(bool aEnabled);
   virtual nsIFrame* GetAbsoluteContainingBlock(nsIFrame* aFrame);
 #ifdef MOZ_REFLOW_PERF
   virtual NS_HIDDEN_(void) DumpReflows() = 0;
   virtual NS_HIDDEN_(void) CountReflows(const char * aName, nsIFrame * aFrame) = 0;
   virtual NS_HIDDEN_(void) PaintCount(const char * aName,
                                       nsRenderingContext* aRenderingContext,
                                       nsPresContext * aPresContext,
                                       nsIFrame * aFrame,
                                       const nsPoint& aOffset,
                                       uint32_t aColor) = 0;
   virtual NS_HIDDEN_(void) SetPaintFrameCount(bool aOn) = 0;
   virtual bool IsPaintingFrameCounts() = 0;
 #endif
 #ifdef DEBUG
   // Debugging hooks
   virtual void ListStyleContexts(nsIFrame *aRootFrame, FILE *out,
                                  int32_t aIndent = 0) = 0;
   virtual void ListStyleSheets(FILE *out, int32_t aIndent = 0) = 0;
   virtual void VerifyStyleTree() = 0;
 #endif
 #ifdef ACCESSIBILITY
   /**
    * Return true if accessibility is active.
    */
   static bool IsAccessibilityActive();
   /**
    * Return accessibility service if accessibility is active.
    */
   static nsAccessibilityService* AccService();
 #endif
   /**
    * Stop all active elements (plugins and the caret) in this presentation and
    * in the presentations of subdocuments.  Resets painting to a suppressed state.
    * XXX this should include image animations
    */
   virtual void Freeze() = 0;
   bool IsFrozen() { return mFrozen; }
   /**
    * Restarts active elements (plugins) in this presentation and in the
    * presentations of subdocuments, then do a full invalidate of the content area.
    */
   virtual void Thaw() = 0;
   virtual void FireOrClearDelayedEvents(bool aFireEvents) = 0;
   /**
    * When this shell is disconnected from its containing docshell, we
    * lose our container pointer.  However, we'd still like to be able to target
    * user events at the docshell's parent.  This pointer allows us to do that.
    * It should not be used for any other purpose.
    */
   void SetForwardingContainer(const mozilla::WeakPtr<nsDocShell> &aContainer);
   /**
    * Render the document into an arbitrary gfxContext
    * Designed for getting a picture of a document or a piece of a document
    * Note that callers will generally want to call FlushPendingNotifications
    * to get an up-to-date view of the document
    * @param aRect is the region to capture into the offscreen buffer, in the
    * root frame's coordinate system (if aIgnoreViewportScrolling is false)
    * or in the root scrolled frame's coordinate system
    * (if aIgnoreViewportScrolling is true). The coordinates are in appunits.
    * @param aFlags see below;
    *   set RENDER_IS_UNTRUSTED if the contents may be passed to malicious
    * agents. E.g. we might choose not to paint the contents of sensitive widgets
    * such as the file name in a file upload widget, and we might choose not
    * to paint themes.
    *   set RENDER_IGNORE_VIEWPORT_SCROLLING to ignore
    * clipping/scrolling/scrollbar painting due to scrolling in the viewport
    *   set RENDER_CARET to draw the caret if one would be visible
    * (by default the caret is never drawn)
    *   set RENDER_USE_LAYER_MANAGER to force rendering to go through
    * the layer manager for the window. This may be unexpectedly slow
    * (if the layer manager must read back data from the GPU) or low-quality
    * (if the layer manager reads back pixel data and scales it
    * instead of rendering using the appropriate scaling). It may also
    * slow everything down if the area rendered does not correspond to the
    * normal visible area of the window.
    *   set RENDER_ASYNC_DECODE_IMAGES to avoid having images synchronously
    * decoded during rendering.
    * (by default images decode synchronously with RenderDocument)
    *   set RENDER_DOCUMENT_RELATIVE to interpret |aRect| relative to the
    * document instead of the CSS viewport
    * @param aBackgroundColor a background color to render onto
    * @param aRenderedContext the gfxContext to render to. We render so that
    * one CSS pixel in the source document is rendered to one unit in the current
    * transform.
    */
   enum {
     RENDER_IS_UNTRUSTED = 0x01,
     RENDER_IGNORE_VIEWPORT_SCROLLING = 0x02,
     RENDER_CARET = 0x04,
     RENDER_USE_WIDGET_LAYERS = 0x08,
     RENDER_ASYNC_DECODE_IMAGES = 0x10,
     RENDER_DOCUMENT_RELATIVE = 0x20,
     RENDER_DRAWWINDOW_NOT_FLUSHING = 0x40
   };
   virtual NS_HIDDEN_(nsresult) RenderDocument(const nsRect& aRect, uint32_t aFlags,
                                               nscolor aBackgroundColor,
                                               gfxContext* aRenderedContext) = 0;
   /**
    * Renders a node aNode to a surface and returns it. The aRegion may be used
    * to clip the rendering. This region is measured in CSS pixels from the
    * edge of the presshell area. The aPoint, aScreenRect and aSurface
    * arguments function in a similar manner as RenderSelection.
    */
   virtual mozilla::TemporaryRef<SourceSurface>
   RenderNode(nsIDOMNode* aNode,
              nsIntRegion* aRegion,
              nsIntPoint& aPoint,
              nsIntRect* aScreenRect) = 0;
   /**
    * Renders a selection to a surface and returns it. This method is primarily
    * intended to create the drag feedback when dragging a selection.
    *
    * aScreenRect will be filled in with the bounding rectangle of the
    * selection area on screen.
    *
    * If the area of the selection is large, the image will be scaled down.
    * The argument aPoint is used in this case as a reference point when
    * determining the new screen rectangle after scaling. Typically, this
    * will be the mouse position, so that the screen rectangle is positioned
    * such that the mouse is over the same point in the scaled image as in
    * the original. When scaling does not occur, the mouse point isn't used
    * as the position can be determined from the displayed frames.
    */
   virtual mozilla::TemporaryRef<SourceSurface>
   RenderSelection(nsISelection* aSelection,
                   nsIntPoint& aPoint,
                   nsIntRect* aScreenRect) = 0;
   void AddWeakFrameInternal(nsWeakFrame* aWeakFrame);
   virtual void AddWeakFrameExternal(nsWeakFrame* aWeakFrame);
   void AddWeakFrame(nsWeakFrame* aWeakFrame)
   {
 #ifdef MOZILLA_INTERNAL_API
     AddWeakFrameInternal(aWeakFrame);
 #else
     AddWeakFrameExternal(aWeakFrame);
 #endif
   }
   void RemoveWeakFrameInternal(nsWeakFrame* aWeakFrame);
   virtual void RemoveWeakFrameExternal(nsWeakFrame* aWeakFrame);
   void RemoveWeakFrame(nsWeakFrame* aWeakFrame)
   {
 #ifdef MOZILLA_INTERNAL_API
     RemoveWeakFrameInternal(aWeakFrame);
 #else
     RemoveWeakFrameExternal(aWeakFrame);
 #endif
   }
 #ifdef DEBUG
   nsIFrame* GetDrawEventTargetFrame() { return mDrawEventTargetFrame; }
 #endif
   /**
    * Stop or restart non synthetic test mouse event handling on *all*
    * presShells.
    *
    * @param aDisable If true, disable all non synthetic test mouse
    * events on all presShells.  Otherwise, enable them.
    */
   virtual NS_HIDDEN_(void) DisableNonTestMouseEvents(bool aDisable) = 0;
   /**
    * Record the background color of the most recently drawn canvas. This color
    * is composited on top of the user's default background color and then used
    * to draw the background color of the canvas. See PresShell::Paint,
    * PresShell::PaintDefaultBackground, and nsDocShell::SetupNewViewer;
    * bug 488242, bug 476557 and other bugs mentioned there.
    */
   void SetCanvasBackground(nscolor aColor) { mCanvasBackgroundColor = aColor; }
   nscolor GetCanvasBackground() { return mCanvasBackgroundColor; }
   /**
    * Use the current frame tree (if it exists) to update the background
    * color of the most recently drawn canvas.
    */
   virtual void UpdateCanvasBackground() = 0;
   /**
    * Add a solid color item to the bottom of aList with frame aFrame and bounds
    * aBounds. Checks first if this needs to be done by checking if aFrame is a
    * canvas frame (if the FORCE_DRAW flag is passed then this check is skipped).
    * aBackstopColor is composed behind the background color of the canvas, it is
    * transparent by default.
    */
   enum {
     FORCE_DRAW = 0x01
   };
   virtual void AddCanvasBackgroundColorItem(nsDisplayListBuilder& aBuilder,
                                             nsDisplayList& aList,
                                             nsIFrame* aFrame,
                                             const nsRect& aBounds,
                                             nscolor aBackstopColor = NS_RGBA(0,0,0,0),
                                             uint32_t aFlags = 0) = 0;
   /**
    * Add a solid color item to the bottom of aList with frame aFrame and
    * bounds aBounds representing the dark grey background behind the page of a
    * print preview presentation.
    */
   virtual void AddPrintPreviewBackgroundItem(nsDisplayListBuilder& aBuilder,
                                              nsDisplayList& aList,
                                              nsIFrame* aFrame,
                                              const nsRect& aBounds) = 0;
   /**
    * Computes the backstop color for the view: transparent if in a transparent
    * widget, otherwise the PresContext default background color. This color is
    * only visible if the contents of the view as a whole are translucent.
    */
   virtual nscolor ComputeBackstopColor(nsView* aDisplayRoot) = 0;
   void ObserveNativeAnonMutationsForPrint(bool aObserve)
   {
     mObservesMutationsForPrint = aObserve;
   }
   bool ObservesNativeAnonMutationsForPrint()
   {
     return mObservesMutationsForPrint;
   }
   virtual nsresult SetIsActive(bool aIsActive) = 0;
   bool IsActive()
   {
     return mIsActive;
   }
   // mouse capturing
   static CapturingContentInfo gCaptureInfo;
   static nsRefPtrHashtable<nsUint32HashKey, mozilla::dom::Touch>* gCaptureTouchList;
   static bool gPreventMouseEvents;
   // Keeps a map between pointerId and element that currently capturing pointer
   // with such pointerId. If pointerId is absent in this map then nobody is
   // capturing it.
   static nsRefPtrHashtable<nsUint32HashKey, nsIContent>* gPointerCaptureList;
   struct PointerInfo
   {
     bool      mActiveState;
     uint16_t  mPointerType;
     PointerInfo(bool aActiveState, uint16_t aPointerType) :
       mActiveState(aActiveState), mPointerType(aPointerType) {}
   };
   // Keeps information about pointers such as pointerId, activeState, pointerType
   static nsClassHashtable<nsUint32HashKey, PointerInfo>* gActivePointersIds;
   static void DispatchGotOrLostPointerCaptureEvent(bool aIsGotCapture,
                                                     uint32_t aPointerId,
                                                     nsIContent* aCaptureTarget);
   static void SetPointerCapturingContent(uint32_t aPointerId, nsIContent* aContent);
   static void ReleasePointerCapturingContent(uint32_t aPointerId, nsIContent* aContent);
   static nsIContent* GetPointerCapturingContent(uint32_t aPointerId);
   // GetPointerInfo returns true if pointer with aPointerId is situated in device, false otherwise.
   // aActiveState is additional information, which shows state of pointer like button state for mouse.
   static bool GetPointerInfo(uint32_t aPointerId, bool& aActiveState);
   /**
    * When capturing content is set, it traps all mouse events and retargets
    * them at this content node. If capturing is not allowed
    * (gCaptureInfo.mAllowed is false), then capturing is not set. However, if
    * the CAPTURE_IGNOREALLOWED flag is set, the allowed state is ignored and
    * capturing is set regardless. To disable capture, pass null for the value
    * of aContent.
    *
    * If CAPTURE_RETARGETTOELEMENT is set, all mouse events are targeted at
    * aContent only. Otherwise, mouse events are targeted at aContent or its
    * descendants. That is, descendants of aContent receive mouse events as
    * they normally would, but mouse events outside of aContent are retargeted
    * to aContent.
    *
    * If CAPTURE_PREVENTDRAG is set then drags are prevented from starting while
    * this capture is active.
    *
    * If CAPTURE_POINTERLOCK is set, similar to CAPTURE_RETARGETTOELEMENT, then
    * events are targeted at aContent, but capturing is held more strongly (i.e.,
    * calls to SetCapturingContent won't unlock unless CAPTURE_POINTERLOCK is
    * set again).
    */
   static void SetCapturingContent(nsIContent* aContent, uint8_t aFlags);
   /**
    * Return the active content currently capturing the mouse if any.
    */
   static nsIContent* GetCapturingContent()
   {
     return gCaptureInfo.mContent;
   }
   /**
    * Allow or disallow mouse capturing.
    */
   static void AllowMouseCapture(bool aAllowed)
   {
     gCaptureInfo.mAllowed = aAllowed;
   }
   /**
    * Returns true if there is an active mouse capture that wants to prevent
    * drags.
    */
   static bool IsMouseCapturePreventingDrag()
   {
     return gCaptureInfo.mPreventDrag && gCaptureInfo.mContent;
   }
   /**
    * Keep track of how many times this presshell has been rendered to
    * a window.
    */
   uint64_t GetPaintCount() { return mPaintCount; }
   void IncrementPaintCount() { ++mPaintCount; }
   /**
    * Get the root DOM window of this presShell.
    */
   virtual already_AddRefed<nsPIDOMWindow> GetRootWindow() = 0;
   /**
    * Get the layer manager for the widget of the root view, if it has
    * one.
    */
   virtual LayerManager* GetLayerManager() = 0;
   /**
    * Track whether we're ignoring viewport scrolling for the purposes
    * of painting.  If we are ignoring, then layers aren't clipped to
    * the CSS viewport and scrollbars aren't drawn.
    */
   virtual void SetIgnoreViewportScrolling(bool aIgnore) = 0;
   bool IgnoringViewportScrolling() const
   { return mRenderFlags & STATE_IGNORING_VIEWPORT_SCROLLING; }
    /**
    * Set a "resolution" for the document, which if not 1.0 will
    * allocate more or fewer pixels for rescalable content by a factor
    * of |resolution| in both dimensions.  Return NS_OK iff the
    * resolution bounds are sane, and the resolution of this was
    * actually updated.
    *
    * The resolution defaults to 1.0.
    */
   virtual nsresult SetResolution(float aXResolution, float aYResolution) = 0;
   gfxSize GetResolution() { return gfxSize(mXResolution, mYResolution); }
   float GetXResolution() { return mXResolution; }
   float GetYResolution() { return mYResolution; }
   virtual gfxSize GetCumulativeResolution() = 0;
   /**
    * Returns whether we are in a DrawWindow() call that used the
    * DRAWWINDOW_DO_NOT_FLUSH flag.
    */
   bool InDrawWindowNotFlushing() const
   { return mRenderFlags & STATE_DRAWWINDOW_NOT_FLUSHING; }
   /**
    * Set the isFirstPaint flag.
    */
   void SetIsFirstPaint(bool aIsFirstPaint) { mIsFirstPaint = aIsFirstPaint; }
   /**
    * Get the isFirstPaint flag.
    */
   bool GetIsFirstPaint() const { return mIsFirstPaint; }
   uint32_t GetPresShellId() { return mPresShellId; }
   /**
    * Dispatch a mouse move event based on the most recent mouse position if
    * this PresShell is visible. This is used when the contents of the page
    * moved (aFromScroll is false) or scrolled (aFromScroll is true).
    */
   virtual void SynthesizeMouseMove(bool aFromScroll) = 0;
   enum PaintFlags {
     /* Update the layer tree and paint ThebesLayers. If this is not specified,
      * we may still have to do it if the layer tree lost ThebesLayer contents
      * we need for compositing. */
     PAINT_LAYERS = 0x01,
     /* Composite layers to the window. */
     PAINT_COMPOSITE = 0x02,
   };
   virtual void Paint(nsView* aViewToPaint, const nsRegion& aDirtyRegion,
                      uint32_t aFlags) = 0;
   virtual nsresult HandleEvent(nsIFrame* aFrame,
                                mozilla::WidgetGUIEvent* aEvent,
                                bool aDontRetargetEvents,
                                nsEventStatus* aEventStatus) = 0;
   virtual bool ShouldIgnoreInvalidation() = 0;
   /**
    * Notify that we're going to call Paint with PAINT_LAYERS
    * on the pres shell for a widget (which might not be this one, since
    * WillPaint is called on all presshells in the same toplevel window as the
    * painted widget). This is issued at a time when it's safe to modify
    * widget geometry.
    */
   virtual void WillPaint() = 0;
   /**
    * Notify that we're going to call Paint with PAINT_COMPOSITE.
    * Fires on the presshell for the painted widget.
    * This is issued at a time when it's safe to modify widget geometry.
    */
   virtual void WillPaintWindow() = 0;
   /**
    * Notify that we called Paint with PAINT_COMPOSITE.
    * Fires on the presshell for the painted widget.
    * This is issued at a time when it's safe to modify widget geometry.
    */
   virtual void DidPaintWindow() = 0;
   /**
    * Ensures that the refresh driver is running, and schedules a view
    * manager flush on the next tick.
    *
    * @param aType PAINT_DELAYED_COMPRESS : Schedule a paint to be executed after a delay, and
    * put FrameLayerBuilder in 'compressed' mode that avoids short cut optimizations.
    */
   enum PaintType {
     PAINT_DEFAULT,
     PAINT_DELAYED_COMPRESS
   };
   virtual void ScheduleViewManagerFlush(PaintType aType = PAINT_DEFAULT) = 0;
   virtual void ClearMouseCaptureOnView(nsView* aView) = 0;
   virtual bool IsVisible() = 0;
   virtual void DispatchSynthMouseMove(mozilla::WidgetGUIEvent* aEvent,
                                       bool aFlushOnHoverChange) = 0;
   virtual void AddSizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf,
                                       nsArenaMemoryStats *aArenaObjectsSize,
                                       size_t *aPresShellSize,
                                       size_t *aStyleSetsSize,
                                       size_t *aTextRunsSize,
                                       size_t *aPresContextSize) = 0;
   /**
    * Methods that retrieve the cached font inflation preferences.
    */
   uint32_t FontSizeInflationEmPerLine() const {
     return mFontSizeInflationEmPerLine;
   }
   uint32_t FontSizeInflationMinTwips() const {
     return mFontSizeInflationMinTwips;
   }
   uint32_t FontSizeInflationLineThreshold() const {
     return mFontSizeInflationLineThreshold;
   }
   bool FontSizeInflationForceEnabled() const {
     return mFontSizeInflationForceEnabled;
   }
   bool FontSizeInflationDisabledInMasterProcess() const {
     return mFontSizeInflationDisabledInMasterProcess;
   }
   /**
    * Determine if font size inflation is enabled. This value is cached until
    * it becomes dirty.
    *
    * @returns true, if font size inflation is enabled; false otherwise.
    */
   bool FontSizeInflationEnabled();
   /**
    * Notify the pres shell that an event occurred making the current value of
    * mFontSizeInflationEnabled invalid. This will schedule a recomputation of
    * whether font size inflation is enabled on the next call to
    * FontSizeInflationEnabled().
    */
   void NotifyFontSizeInflationEnabledIsDirty()
   {
     mFontSizeInflationEnabledIsDirty = true;
   }
   virtual void AddInvalidateHiddenPresShellObserver(nsRefreshDriver *aDriver) = 0;
   void InvalidatePresShellIfHidden();
   void CancelInvalidatePresShellIfHidden();
   // Schedule an update of the list of visible images.
   virtual void ScheduleImageVisibilityUpdate() = 0;
   // Clears the current list of visible images on this presshell and replaces it
   // with images that are in the display list aList.
   virtual void RebuildImageVisibility(const nsDisplayList& aList) = 0;
   // Ensures the image is in the list of visible images.
   virtual void EnsureImageInVisibleList(nsIImageLoadingContent* aImage) = 0;
   // Removes the image from the list of visible images if it is present there.
   virtual void RemoveImageFromVisibleList(nsIImageLoadingContent* aImage) = 0;
   // Whether we should assume all images are visible.
   virtual bool AssumeAllImagesVisible() = 0;
   /**
    * Refresh observer management.
    */
 protected:
   virtual bool AddRefreshObserverExternal(nsARefreshObserver* aObserver,
                                           mozFlushType aFlushType);
   bool AddRefreshObserverInternal(nsARefreshObserver* aObserver,
                                   mozFlushType aFlushType);
   virtual bool RemoveRefreshObserverExternal(nsARefreshObserver* aObserver,
                                              mozFlushType aFlushType);
   bool RemoveRefreshObserverInternal(nsARefreshObserver* aObserver,
                                      mozFlushType aFlushType);
   /**
    * Do computations necessary to determine if font size inflation is enabled.
    * This value is cached after computation, as the computation is somewhat
    * expensive.
    */
   void RecomputeFontSizeInflationEnabled();
 public:
   bool AddRefreshObserver(nsARefreshObserver* aObserver,
                           mozFlushType aFlushType) {
 #ifdef MOZILLA_INTERNAL_API
     return AddRefreshObserverInternal(aObserver, aFlushType);
 #else
     return AddRefreshObserverExternal(aObserver, aFlushType);
 #endif
   }
   bool RemoveRefreshObserver(nsARefreshObserver* aObserver,
                              mozFlushType aFlushType) {
 #ifdef MOZILLA_INTERNAL_API
     return RemoveRefreshObserverInternal(aObserver, aFlushType);
 #else
     return RemoveRefreshObserverExternal(aObserver, aFlushType);
 #endif
   }
   virtual bool AddPostRefreshObserver(nsAPostRefreshObserver* aObserver);
   virtual bool RemovePostRefreshObserver(nsAPostRefreshObserver* aObserver);
   /**
    * Initialize and shut down static variables.
    */
   static void InitializeStatics();
   static void ReleaseStatics();
   // If a frame in the subtree rooted at aFrame is capturing the mouse then
   // clears that capture.
   static void ClearMouseCapture(nsIFrame* aFrame);
   void SetScrollPositionClampingScrollPortSize(nscoord aWidth, nscoord aHeight);
   bool IsScrollPositionClampingScrollPortSizeSet() {
     return mScrollPositionClampingScrollPortSizeSet;
   }
   nsSize GetScrollPositionClampingScrollPortSize() {
     NS_ASSERTION(mScrollPositionClampingScrollPortSizeSet, "asking for scroll port when its not set?");
     return mScrollPositionClampingScrollPortSize;
   }
   void SetContentDocumentFixedPositionMargins(const nsMargin& aMargins);
   const nsMargin& GetContentDocumentFixedPositionMargins() {
     return mContentDocumentFixedPositionMargins;
   }
   virtual void WindowSizeMoveDone() = 0;
   virtual void SysColorChanged() = 0;
   virtual void ThemeChanged() = 0;
   virtual void BackingScaleFactorChanged() = 0;
   nscoord MaxLineBoxWidth() {
     return mMaxLineBoxWidth;
   }
   void SetMaxLineBoxWidth(nscoord aMaxLineBoxWidth);
   /**
    * Returns whether or not there is a reflow on zoom event pending. A reflow
    * on zoom event is a change to the max line box width, followed by a reflow.
    * This subsequent reflow event should treat all frames as though they resized
    * horizontally (and thus reflow all their descendants), rather than marking
    * all frames dirty from the root. This is the way the pres shell indicates
    * that an hresize reflow should take place during reflow state construction.
    */
   bool IsReflowOnZoomPending() {
     return mReflowOnZoomPending;
   }
   /**
    * Clear the flag indicating whether a reflow on zoom event is pending. This
    * is performed at the very end of DoReflow().
    */
   void ClearReflowOnZoomPending() {
     mReflowOnZoomPending = false;
   }
   /**
    * Documents belonging to an invisible DocShell must not be painted ever.
    */
   bool IsNeverPainting() {
     return mIsNeverPainting;
   }
   void SetNeverPainting(bool aNeverPainting) {
     mIsNeverPainting = aNeverPainting;
   }
 protected:
   friend class nsRefreshDriver;
   // IMPORTANT: The ownership implicit in the following member variables
   // has been explicitly checked.  If you add any members to this class,
   // please make the ownership explicit (pinkerton, scc).
   // These are the same Document and PresContext owned by the DocViewer.
   // we must share ownership.
   nsIDocument*              mDocument;      // [STRONG]
   nsPresContext*            mPresContext;   // [STRONG]
   nsStyleSet*               mStyleSet;      // [OWNS]
   nsCSSFrameConstructor*    mFrameConstructor; // [OWNS]
   nsViewManager*           mViewManager;   // [WEAK] docViewer owns it so I don't have to
   nsPresArena               mFrameArena;
   nsFrameSelection*         mSelection;
   // Pointer into mFrameConstructor - this is purely so that FrameManager() and
   // GetRootFrame() can be inlined:
   nsFrameManagerBase*       mFrameManager;
   mozilla::WeakPtr<nsDocShell>                 mForwardingContainer;
   nsRefreshDriver*          mHiddenInvalidationObserverRefreshDriver;
 #ifdef ACCESSIBILITY
   mozilla::a11y::DocAccessible* mDocAccessible;
 #endif
 #ifdef DEBUG
   nsIFrame*                 mDrawEventTargetFrame;
   // Ensure that every allocation from the PresArena is eventually freed.
   uint32_t                  mPresArenaAllocCount;
 #endif
   // Count of the number of times this presshell has been painted to a window.
   uint64_t                  mPaintCount;
   nsSize                    mScrollPositionClampingScrollPortSize;
   // This margin is intended to be used when laying out fixed position children
   // on this PresShell's viewport frame. See the documentation of
   // nsIDOMWindowUtils.setContentDocumentFixedPositionMargins for details of
   // their use.
   nsMargin                  mContentDocumentFixedPositionMargins;
   // A list of weak frames. This is a pointer to the last item in the list.
   nsWeakFrame*              mWeakFrames;
   // Most recent canvas background color.
   nscolor                   mCanvasBackgroundColor;
   // Used to force allocation and rendering of proportionally more or
   // less pixels in the given dimension.
   float                     mXResolution;
   float                     mYResolution;
   int16_t                   mSelectionFlags;
   // Flags controlling how our document is rendered.  These persist
   // between paints and so are tied with retained layer pixels.
   // PresShell flushes retained layers when the rendering state
   // changes in a way that prevents us from being able to (usefully)
   // re-use old pixels.
   RenderFlags               mRenderFlags;
   // Indicates that the whole document must be restyled.  Changes to scoped
   // style sheets are recorded in mChangedScopeStyleRoots rather than here
   // in mStylesHaveChanged.
   bool                      mStylesHaveChanged : 1;
   bool                      mDidInitialize : 1;
   bool                      mIsDestroying : 1;
   bool                      mIsZombie : 1;
   bool                      mIsReflowing : 1;
   // For all documents we initially lock down painting.
   bool                      mPaintingSuppressed : 1;
   // Whether or not form controls should use nsITheme in this shell.
   bool                      mIsThemeSupportDisabled : 1;
   bool                      mIsActive : 1;
   bool                      mFrozen : 1;
   bool                      mIsFirstPaint : 1;
   bool                      mObservesMutationsForPrint : 1;
   // If true, we have a reflow scheduled. Guaranteed to be false if
   // mReflowContinueTimer is non-null.
   bool                      mReflowScheduled : 1;
   bool                      mSuppressInterruptibleReflows : 1;
   bool                      mScrollPositionClampingScrollPortSizeSet : 1;
   uint32_t                  mPresShellId;
   // List of subtrees rooted at style scope roots that need to be restyled.
   // When a change to a scoped style sheet is made, we add the style scope
   // root to this array rather than setting mStylesHaveChanged = true, since
   // we know we don't need to restyle the whole document.  However, if in the
   // same update block we have already had other changes that require
   // the whole document to be restyled (i.e., mStylesHaveChanged is already
   // true), then we don't bother adding the scope root here.
   nsAutoTArray<nsRefPtr<mozilla::dom::Element>,1> mChangedScopeStyleRoots;
   static nsIContent*        gKeyDownTarget;
   // Cached font inflation values. This is done to prevent changing of font
   // inflation until a page is reloaded.
   uint32_t mFontSizeInflationEmPerLine;
   uint32_t mFontSizeInflationMinTwips;
   uint32_t mFontSizeInflationLineThreshold;
   bool mFontSizeInflationForceEnabled;
   bool mFontSizeInflationDisabledInMasterProcess;
   bool mFontSizeInflationEnabled;
   bool mPaintingIsFrozen;
   // Dirty bit indicating that mFontSizeInflationEnabled needs to be recomputed.
   bool mFontSizeInflationEnabledIsDirty;
   // Flag to indicate whether or not there is a reflow on zoom event pending.
   // See IsReflowOnZoomPending() for more information.
   bool mReflowOnZoomPending;
   // The maximum width of a line box. Text on a single line that exceeds this
   // width will be wrapped. A value of 0 indicates that no limit is enforced.
   nscoord mMaxLineBoxWidth;
   // If a document belongs to an invisible DocShell, this flag must be set
   // to true, so we can avoid any paint calls for widget related to this
   // presshell.
   bool mIsNeverPainting;
 };
 NS_DEFINE_STATIC_IID_ACCESSOR(nsIPresShell, NS_IPRESSHELL_IID)
 #endif /* nsIPresShell_h___ */

The Tor Browser / annotate

layout/base/nsIPresShell.h@b8a032363ba2 (annotated)

layout/base/nsIPresShell.h