diff -r 000000000000 -r 6474c204b198 layout/xul/nsXULLabelFrame.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/layout/xul/nsXULLabelFrame.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,116 @@
+/* -*- 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/. */
+
+/* derived class of nsBlockFrame used for xul:label elements */
+
+#include "mozilla/EventStateManager.h"
+#include "nsXULLabelFrame.h"
+#include "nsHTMLParts.h"
+#include "nsNameSpaceManager.h"
+
+using namespace mozilla;
+
+nsIFrame*
+NS_NewXULLabelFrame(nsIPresShell* aPresShell, nsStyleContext* aContext)
+{
+  nsXULLabelFrame* it = new (aPresShell) nsXULLabelFrame(aContext);
+  
+  it->SetFlags(NS_BLOCK_FLOAT_MGR | NS_BLOCK_MARGIN_ROOT);
+
+  return it;
+}
+
+NS_IMPL_FRAMEARENA_HELPERS(nsXULLabelFrame)
+
+// If you make changes to this function, check its counterparts 
+// in nsBoxFrame and nsTextBoxFrame
+nsresult
+nsXULLabelFrame::RegUnregAccessKey(bool aDoReg)
+{
+  // if we have no content, we can't do anything
+  if (!mContent)
+    return NS_ERROR_FAILURE;
+
+  // To filter out <label>s without a control attribute.
+  // XXXjag a side-effect is that we filter out anonymous <label>s
+  // in e.g. <menu>, <menuitem>, <button>. These <label>s inherit
+  // |accesskey| and would otherwise register themselves, overwriting
+  // the content we really meant to be registered.
+  if (!mContent->HasAttr(kNameSpaceID_None, nsGkAtoms::control))
+    return NS_OK;
+
+  nsAutoString accessKey;
+  mContent->GetAttr(kNameSpaceID_None, nsGkAtoms::accesskey, accessKey);
+
+  if (accessKey.IsEmpty())
+    return NS_OK;
+
+  // With a valid PresContext we can get the ESM 
+  // and register the access key
+  EventStateManager* esm = PresContext()->EventStateManager();
+
+  uint32_t key = accessKey.First();
+  if (aDoReg)
+    esm->RegisterAccessKey(mContent, key);
+  else
+    esm->UnregisterAccessKey(mContent, key);
+
+  return NS_OK;
+}
+
+/////////////////////////////////////////////////////////////////////////////
+// nsIFrame
+
+void
+nsXULLabelFrame::Init(nsIContent*      aContent,
+                      nsIFrame*        aParent,
+                      nsIFrame*        aPrevInFlow)
+{
+  nsBlockFrame::Init(aContent, aParent, aPrevInFlow);
+
+  // register access key
+  RegUnregAccessKey(true);
+}
+
+void
+nsXULLabelFrame::DestroyFrom(nsIFrame* aDestructRoot)
+{
+  // unregister access key
+  RegUnregAccessKey(false);
+  nsBlockFrame::DestroyFrom(aDestructRoot);
+} 
+
+nsresult
+nsXULLabelFrame::AttributeChanged(int32_t aNameSpaceID,
+                                  nsIAtom* aAttribute,
+                                  int32_t aModType)
+{
+  nsresult rv = nsBlockFrame::AttributeChanged(aNameSpaceID, 
+                                               aAttribute, aModType);
+
+  // If the accesskey changed, register for the new value
+  // The old value has been unregistered in nsXULElement::SetAttr
+  if (aAttribute == nsGkAtoms::accesskey || aAttribute == nsGkAtoms::control)
+    RegUnregAccessKey(true);
+
+  return rv;
+}
+
+nsIAtom*
+nsXULLabelFrame::GetType() const
+{
+  return nsGkAtoms::XULLabelFrame;
+}
+
+/////////////////////////////////////////////////////////////////////////////
+// Diagnostics
+
+#ifdef DEBUG_FRAME_DUMP
+nsresult
+nsXULLabelFrame::GetFrameName(nsAString& aResult) const
+{
+  return MakeFrameName(NS_LITERAL_STRING("XULLabel"), aResult);
+}
+#endif