Bug 1340771 part 2 - Introduce a WeakFrame class for heap allocated weak frame pointers, stored in a hashtable for fast lookup. r=tn

* * *
Bug 1340771 part 3 - Change existing heap allocated AutoWeakFrame instances to use WeakFrame instead.  r=tn

MozReview-Commit-ID: GSuUiy98jBa

accessible/base/SelectionManager.h

@@ -121,7 +121,7 @@ protected:
 
 private:
   // Currently focused control.
-  AutoWeakFrame mCurrCtrlFrame;
+  WeakFrame mCurrCtrlFrame;
   int32_t mCaretOffset;
   HyperTextAccessible* mAccWithCaret;
 };

dom/base/nsFrameLoader.h

@@ -329,7 +329,7 @@ private:
 
   // Stores the root frame of the subdocument while the subdocument is being
   // reframed. Used to restore the presentation after reframing.
-  AutoWeakFrame mDetachedSubdocFrame;
+  WeakFrame mDetachedSubdocFrame;
   // Stores the containing document of the frame corresponding to this
   // frame loader. This is reference is kept valid while the subframe's
   // presentation is detached and stored in mDetachedSubdocFrame. This

dom/base/nsObjectLoadingContent.h

@@ -715,7 +715,7 @@ class nsObjectLoadingContent : public nsImageLoadingContent
     bool                        mPreferFallback : 1;
     bool                        mPreferFallbackKnown : 1;
 
-    AutoWeakFrame                 mPrintFrame;
+    WeakFrame                   mPrintFrame;
 
     RefPtr<nsPluginInstanceOwner> mInstanceOwner;
     nsTArray<mozilla::dom::MozPluginParameter> mCachedAttributes;

dom/events/EventStateManager.cpp

@@ -4450,8 +4450,9 @@ EventStateManager::GenerateDragDropEnterExit(nsPresContext* aPresContext,
           }
         }
 
+        AutoWeakFrame currentTraget = mCurrentTarget;
         FireDragEnterOrExit(aPresContext, aDragEvent, eDragEnter,
-                            lastContent, targetContent, mCurrentTarget);
+                            lastContent, targetContent, currentTraget);
 
         if (sLastDragOverFrame) {
           FireDragEnterOrExit(sLastDragOverFrame->PresContext(),

dom/events/EventStateManager.h

@@ -54,7 +54,7 @@ public:
   NS_DECL_CYCLE_COLLECTING_ISUPPORTS
   NS_DECL_CYCLE_COLLECTION_CLASS(OverOutElementsWrapper)
 
-  AutoWeakFrame mLastOverFrame;
+  WeakFrame mLastOverFrame;
 
   nsCOMPtr<nsIContent> mLastOverElement;
 
@@ -930,7 +930,7 @@ private:
   // to content.
   static LayoutDeviceIntPoint sSynthCenteringPoint;
 
-  AutoWeakFrame mCurrentTarget;
+  WeakFrame mCurrentTarget;
   nsCOMPtr<nsIContent> mCurrentTargetContent;
   static AutoWeakFrame sLastDragOverFrame;
 

layout/base/PresShell.cpp

@@ -665,35 +665,51 @@ nsIPresShell::SetVerifyReflowEnable(bool aEnabled)
 }
 
 /* virtual */ void
-nsIPresShell::AddWeakFrameExternal(AutoWeakFrame* aWeakFrame)
+nsIPresShell::AddAutoWeakFrameExternal(AutoWeakFrame* aWeakFrame)
+{
+  AddAutoWeakFrameInternal(aWeakFrame);
+}
+
+void
+nsIPresShell::AddAutoWeakFrameInternal(AutoWeakFrame* aWeakFrame)
+{
+  if (aWeakFrame->GetFrame()) {
+    aWeakFrame->GetFrame()->AddStateBits(NS_FRAME_EXTERNAL_REFERENCE);
+  }
+  aWeakFrame->SetPreviousWeakFrame(mAutoWeakFrames);
+  mAutoWeakFrames = aWeakFrame;
+}
+
+/* virtual */ void
+nsIPresShell::AddWeakFrameExternal(WeakFrame* aWeakFrame)
 {
   AddWeakFrameInternal(aWeakFrame);
 }
 
 void
-nsIPresShell::AddWeakFrameInternal(AutoWeakFrame* aWeakFrame)
+nsIPresShell::AddWeakFrameInternal(WeakFrame* aWeakFrame)
 {
   if (aWeakFrame->GetFrame()) {
     aWeakFrame->GetFrame()->AddStateBits(NS_FRAME_EXTERNAL_REFERENCE);
   }
-  aWeakFrame->SetPreviousWeakFrame(mWeakFrames);
-  mWeakFrames = aWeakFrame;
+  MOZ_ASSERT(!mWeakFrames.GetEntry(aWeakFrame));
+  mWeakFrames.PutEntry(aWeakFrame);
 }
 
 /* virtual */ void
-nsIPresShell::RemoveWeakFrameExternal(AutoWeakFrame* aWeakFrame)
+nsIPresShell::RemoveAutoWeakFrameExternal(AutoWeakFrame* aWeakFrame)
 {
-  RemoveWeakFrameInternal(aWeakFrame);
+  RemoveAutoWeakFrameInternal(aWeakFrame);
 }
 
 void
-nsIPresShell::RemoveWeakFrameInternal(AutoWeakFrame* aWeakFrame)
+nsIPresShell::RemoveAutoWeakFrameInternal(AutoWeakFrame* aWeakFrame)
 {
-  if (mWeakFrames == aWeakFrame) {
-    mWeakFrames = aWeakFrame->GetPreviousWeakFrame();
+  if (mAutoWeakFrames == aWeakFrame) {
+    mAutoWeakFrames = aWeakFrame->GetPreviousWeakFrame();
     return;
   }
-  AutoWeakFrame* nextWeak = mWeakFrames;
+  AutoWeakFrame* nextWeak = mAutoWeakFrames;
   while (nextWeak && nextWeak->GetPreviousWeakFrame() != aWeakFrame) {
     nextWeak = nextWeak->GetPreviousWeakFrame();
   }
@@ -702,6 +718,19 @@ nsIPresShell::RemoveWeakFrameInternal(AutoWeakFrame* aWeakFrame)
   }
 }
 
+/* virtual */ void
+nsIPresShell::RemoveWeakFrameExternal(WeakFrame* aWeakFrame)
+{
+  RemoveWeakFrameInternal(aWeakFrame);
+}
+
+void
+nsIPresShell::RemoveWeakFrameInternal(WeakFrame* aWeakFrame)
+{
+  MOZ_ASSERT(mWeakFrames.GetEntry(aWeakFrame));
+  mWeakFrames.RemoveEntry(aWeakFrame);
+}
+
 already_AddRefed<nsFrameSelection>
 nsIPresShell::FrameSelection()
 {
@@ -751,7 +780,7 @@ nsIPresShell::nsIPresShell()
     , mDrawEventTargetFrame(nullptr)
 #endif
     , mPaintCount(0)
-    , mWeakFrames(nullptr)
+    , mAutoWeakFrames(nullptr)
     , mCanvasBackgroundColor(NS_RGBA(0,0,0,0))
     , mSelectionFlags(0)
     , mRenderFlags(0)
@@ -1366,10 +1395,17 @@ PresShell::Destroy()
   }
 
 
-  NS_WARNING_ASSERTION(!mWeakFrames,
+  NS_WARNING_ASSERTION(!mAutoWeakFrames && mWeakFrames.IsEmpty(),
                        "Weak frames alive after destroying FrameManager");
-  while (mWeakFrames) {
-    mWeakFrames->Clear(this);
+  while (mAutoWeakFrames) {
+    mAutoWeakFrames->Clear(this);
+  }
+  nsTArray<WeakFrame*> toRemove(mWeakFrames.Count());
+  for (auto iter = mWeakFrames.Iter(); !iter.Done(); iter.Next()) {
+    toRemove.AppendElement(iter.Get()->GetKey());
+  }
+  for (WeakFrame* weakFrame : toRemove) {
+    weakFrame->Clear(this);
   }
 
   // Let the style set do its cleanup.
@@ -2949,15 +2985,26 @@ PresShell::ClearFrameRefs(nsIFrame* aFrame)
 {
   mPresContext->EventStateManager()->ClearFrameRefs(aFrame);
 
-  AutoWeakFrame* weakFrame = mWeakFrames;
+  AutoWeakFrame* weakFrame = mAutoWeakFrames;
   while (weakFrame) {
     AutoWeakFrame* prev = weakFrame->GetPreviousWeakFrame();
     if (weakFrame->GetFrame() == aFrame) {
-      // This removes weakFrame from mWeakFrames.
+      // This removes weakFrame from mAutoWeakFrames.
       weakFrame->Clear(this);
     }
     weakFrame = prev;
   }
+
+  AutoTArray<WeakFrame*, 4> toRemove;
+  for (auto iter = mWeakFrames.Iter(); !iter.Done(); iter.Next()) {
+    WeakFrame* weakFrame = iter.Get()->GetKey();
+    if (weakFrame->GetFrame() == aFrame) {
+      toRemove.AppendElement(weakFrame);
+    }
+  }
+  for (WeakFrame* weakFrame : toRemove) {
+    weakFrame->Clear(this);
+  }
 }
 
 already_AddRefed<gfxContext>

layout/base/nsIPresShell.h

@@ -79,6 +79,7 @@ class nsCSSFrameConstructor;
 class nsISelection;
 template<class E> class nsCOMArray;
 class AutoWeakFrame;
+class WeakFrame;
 class nsIScrollableFrame;
 class gfxContext;
 class nsIDOMEvent;
@@ -1192,10 +1193,20 @@ public:
                   mozilla::LayoutDeviceIntRect* aScreenRect,
                   uint32_t aFlags) = 0;
 
-  void AddWeakFrameInternal(AutoWeakFrame* aWeakFrame);
-  virtual void AddWeakFrameExternal(AutoWeakFrame* aWeakFrame);
+  void AddAutoWeakFrameInternal(AutoWeakFrame* aWeakFrame);
+  virtual void AddAutoWeakFrameExternal(AutoWeakFrame* aWeakFrame);
+  void AddWeakFrameInternal(WeakFrame* aWeakFrame);
+  virtual void AddWeakFrameExternal(WeakFrame* aWeakFrame);
 
-  void AddWeakFrame(AutoWeakFrame* aWeakFrame)
+  void AddAutoWeakFrame(AutoWeakFrame* aWeakFrame)
+  {
+#ifdef MOZILLA_INTERNAL_API
+    AddAutoWeakFrameInternal(aWeakFrame);
+#else
+    AddAutoWeakFrameExternal(aWeakFrame);
+#endif
+  }
+  void AddWeakFrame(WeakFrame* aWeakFrame)
   {
 #ifdef MOZILLA_INTERNAL_API
     AddWeakFrameInternal(aWeakFrame);
@@ -1204,10 +1215,20 @@ public:
 #endif
   }
 
-  void RemoveWeakFrameInternal(AutoWeakFrame* aWeakFrame);
-  virtual void RemoveWeakFrameExternal(AutoWeakFrame* aWeakFrame);
+  void RemoveAutoWeakFrameInternal(AutoWeakFrame* aWeakFrame);
+  virtual void RemoveAutoWeakFrameExternal(AutoWeakFrame* aWeakFrame);
+  void RemoveWeakFrameInternal(WeakFrame* aWeakFrame);
+  virtual void RemoveWeakFrameExternal(WeakFrame* aWeakFrame);
 
-  void RemoveWeakFrame(AutoWeakFrame* aWeakFrame)
+  void RemoveAutoWeakFrame(AutoWeakFrame* aWeakFrame)
+  {
+#ifdef MOZILLA_INTERNAL_API
+    RemoveAutoWeakFrameInternal(aWeakFrame);
+#else
+    RemoveAutoWeakFrameExternal(aWeakFrame);
+#endif
+  }
+  void RemoveWeakFrame(WeakFrame* aWeakFrame)
   {
 #ifdef MOZILLA_INTERNAL_API
     RemoveWeakFrameInternal(aWeakFrame);
@@ -1815,8 +1836,11 @@ protected:
 
   nsSize                    mScrollPositionClampingScrollPortSize;
 
-  // A list of weak frames. This is a pointer to the last item in the list.
-  AutoWeakFrame*              mWeakFrames;
+  // A list of stack weak frames. This is a pointer to the last item in the list.
+  AutoWeakFrame*            mAutoWeakFrames;
+
+  // A hash table of heap allocated weak frames.
+  nsTHashtable<nsPtrHashKey<WeakFrame>> mWeakFrames;
 
   // Most recent canvas background color.
   nscolor                   mCanvasBackgroundColor;

layout/forms/nsComboboxControlFrame.cpp

@@ -413,7 +413,7 @@ public:
     return NS_OK;
   }
 
-  AutoWeakFrame mFrame;
+  WeakFrame mFrame;
 };
 
 void
@@ -527,7 +527,7 @@ public:
     }
     return NS_OK;
   }
-  AutoWeakFrame mFrame;
+  WeakFrame mFrame;
 };
 
 class nsAsyncResize : public Runnable
@@ -556,7 +556,7 @@ public:
     }
     return NS_OK;
   }
-  AutoWeakFrame mFrame;
+  WeakFrame mFrame;
 };
 
 void

layout/forms/nsDateTimeControlFrame.h

@@ -103,7 +103,7 @@ private:
     }
 
   private:
-    AutoWeakFrame mFrame;
+    WeakFrame mFrame;
   };
 
   /**

layout/forms/nsFileControlFrame.h

@@ -111,7 +111,7 @@ protected:
     }
 
   private:
-    AutoWeakFrame mFrame;
+    WeakFrame mFrame;
   };
 
   class DnDListener: public MouseListener {

layout/forms/nsNumberControlFrame.h

@@ -192,7 +192,7 @@ private:
     }
 
   private:
-    AutoWeakFrame mFrame;
+    WeakFrame mFrame;
   };
 
   /**

layout/generic/nsFrame.cpp

@@ -406,6 +406,12 @@ nsIFrame::ContentStatesChanged(mozilla::EventStates aStates)
 {
 }
 
+AutoWeakFrame::AutoWeakFrame(const WeakFrame& aOther)
+  : mPrev(nullptr), mFrame(nullptr)
+{
+  Init(aOther.GetFrame());
+}
+
 void
 AutoWeakFrame::Init(nsIFrame* aFrame)
 {
@@ -414,6 +420,22 @@ AutoWeakFrame::Init(nsIFrame* aFrame)
   if (mFrame) {
     nsIPresShell* shell = mFrame->PresContext()->GetPresShell();
     NS_WARNING_ASSERTION(shell, "Null PresShell in AutoWeakFrame!");
+    if (shell) {
+      shell->AddAutoWeakFrame(this);
+    } else {
+      mFrame = nullptr;
+    }
+  }
+}
+
+void
+WeakFrame::Init(nsIFrame* aFrame)
+{
+  Clear(mFrame ? mFrame->PresContext()->GetPresShell() : nullptr);
+  mFrame = aFrame;
+  if (mFrame) {
+    nsIPresShell* shell = mFrame->PresContext()->GetPresShell();
+    MOZ_ASSERT(shell, "Null PresShell in WeakFrame!");
     if (shell) {
       shell->AddWeakFrame(this);
     } else {

layout/generic/nsIFrame.h

@@ -3818,7 +3818,8 @@ public:
 /**
  * AutoWeakFrame can be used to keep a reference to a nsIFrame in a safe way.
  * Whenever an nsIFrame object is deleted, the AutoWeakFrames pointing
- * to it will be cleared.
+ * to it will be cleared.  AutoWeakFrame is for variables on the stack or
+ * in static storage only, there is also a WeakFrame below for heap uses.
  *
  * Create AutoWeakFrame object when it is sure that nsIFrame object
  * is alive and after some operations which may destroy the nsIFrame
@@ -3827,17 +3828,23 @@ public:
  *
  * @note The usage of this class should be kept to a minimum.
  */
-
-class AutoWeakFrame {
+class WeakFrame;
+class AutoWeakFrame
+{
 public:
-  AutoWeakFrame() : mPrev(nullptr), mFrame(nullptr) { }
+  explicit AutoWeakFrame()
+    : mPrev(nullptr), mFrame(nullptr) {}
 
-  AutoWeakFrame(const AutoWeakFrame& aOther) : mPrev(nullptr), mFrame(nullptr)
+  AutoWeakFrame(const AutoWeakFrame& aOther)
+    : mPrev(nullptr), mFrame(nullptr)
   {
     Init(aOther.GetFrame());
   }
 
-  MOZ_IMPLICIT AutoWeakFrame(nsIFrame* aFrame) : mPrev(nullptr), mFrame(nullptr)
+  MOZ_IMPLICIT AutoWeakFrame(const WeakFrame& aOther);
+
+  MOZ_IMPLICIT AutoWeakFrame(nsIFrame* aFrame)
+    : mPrev(nullptr), mFrame(nullptr)
   {
     Init(aFrame);
   }
@@ -3864,7 +3871,7 @@ public:
 
   void Clear(nsIPresShell* aShell) {
     if (aShell) {
-      aShell->RemoveWeakFrame(this);
+      aShell->RemoveAutoWeakFrame(this);
     }
     mFrame = nullptr;
     mPrev = nullptr;
@@ -3883,10 +3890,73 @@ public:
     Clear(mFrame ? mFrame->PresContext()->GetPresShell() : nullptr);
   }
 private:
+  // Not available for the heap!
+  void* operator new(size_t) = delete;
+  void* operator new[](size_t) = delete;
+  void operator delete(void*) = delete;
+  void operator delete[](void*) = delete;
+
   void Init(nsIFrame* aFrame);
 
   AutoWeakFrame*  mPrev;
-  nsIFrame*     mFrame;
+  nsIFrame*       mFrame;
+};
+
+/**
+ * @see AutoWeakFrame
+ */
+class WeakFrame
+{
+public:
+  WeakFrame() : mFrame(nullptr) {}
+
+  WeakFrame(const WeakFrame& aOther) : mFrame(nullptr)
+  {
+    Init(aOther.GetFrame());
+  }
+
+  MOZ_IMPLICIT WeakFrame(const AutoWeakFrame& aOther) : mFrame(nullptr)
+  {
+    Init(aOther.GetFrame());
+  }
+
+  MOZ_IMPLICIT WeakFrame(nsIFrame* aFrame) : mFrame(nullptr)
+  {
+    Init(aFrame);
+  }
+
+  ~WeakFrame()
+  {
+    Clear(mFrame ? mFrame->PresContext()->GetPresShell() : nullptr);
+  }
+
+  WeakFrame& operator=(WeakFrame& aOther) {
+    Init(aOther.GetFrame());
+    return *this;
+  }
+
+  WeakFrame& operator=(nsIFrame* aFrame) {
+    Init(aFrame);
+    return *this;
+  }
+
+  nsIFrame* operator->() { return mFrame; }
+  operator nsIFrame*() { return mFrame; }
+
+  void Clear(nsIPresShell* aShell) {
+    if (aShell) {
+      aShell->RemoveWeakFrame(this);
+    }
+    mFrame = nullptr;
+  }
+
+  bool IsAlive() { return !!mFrame; }
+  nsIFrame* GetFrame() const { return mFrame; }
+
+private:
+  void Init(nsIFrame* aFrame);
+
+  nsIFrame* mFrame;
 };
 
 inline bool

layout/generic/nsSubDocumentFrame.cpp

@@ -93,7 +93,7 @@ public:
     return NS_OK;
   }
 private:
-  AutoWeakFrame mFrame;
+  WeakFrame mFrame;
 };
 
 static void

layout/painting/ActiveLayerTracker.cpp

@@ -105,7 +105,7 @@ public:
 
   // The scroll frame during for which we most recently received a call to
   // NotifyAnimatedFromScrollHandler.
-  AutoWeakFrame mAnimatingScrollHandlerFrame;
+  WeakFrame mAnimatingScrollHandlerFrame;
   // The set of activities that were triggered during
   // mAnimatingScrollHandlerFrame's scroll event handler.
   EnumSet<ActivityIndex> mScrollHandlerInducedActivity;
@@ -132,7 +132,7 @@ public:
   virtual void NotifyExpired(LayerActivity* aObject);
 
 public:
-  AutoWeakFrame mCurrentScrollHandlerFrame;
+  WeakFrame mCurrentScrollHandlerFrame;
 
 private:
   bool mDestroying;

layout/printing/nsPrintEngine.h

@@ -263,7 +263,7 @@ protected:
   
   mozilla::UniquePtr<nsPrintData> mPrt;
   nsPagePrintTimer*       mPagePrintTimer;
-  AutoWeakFrame             mPageSeqFrame;
+  WeakFrame               mPageSeqFrame;
 
   // Print Preview
   mozilla::UniquePtr<nsPrintData> mPrtPreview;

layout/tables/nsTableFrame.cpp

@@ -4861,7 +4861,7 @@ public:
     return NS_OK;
   }
 private:
-  AutoWeakFrame mFrame;
+  WeakFrame mFrame;
 };
 
 bool

layout/xul/nsListBoxBodyFrame.cpp

@@ -1130,7 +1130,7 @@ nsListBoxBodyFrame::GetFirstItemBox(int32_t aOffset, bool* aCreated)
   mBottomFrame = mTopFrame;
 
   if (mTopFrame) {
-    return mTopFrame->IsXULBoxFrame() ? mTopFrame : nullptr;
+    return mTopFrame->IsXULBoxFrame() ? mTopFrame.GetFrame() : nullptr;
   }
 
   // top frame was cleared out
@@ -1138,7 +1138,7 @@ nsListBoxBodyFrame::GetFirstItemBox(int32_t aOffset, bool* aCreated)
   mBottomFrame = mTopFrame;
 
   if (mTopFrame && mRowsToPrepend <= 0) {
-    return mTopFrame->IsXULBoxFrame() ? mTopFrame : nullptr;
+    return mTopFrame->IsXULBoxFrame() ? mTopFrame.GetFrame() : nullptr;
   }
 
   // At this point, we either have no frames at all, 
@@ -1187,7 +1187,7 @@ nsListBoxBodyFrame::GetFirstItemBox(int32_t aOffset, bool* aCreated)
 
       mBottomFrame = mTopFrame;
 
-      return mTopFrame->IsXULBoxFrame() ? mTopFrame : nullptr;
+      return mTopFrame->IsXULBoxFrame() ? mTopFrame.GetFrame() : nullptr;
     } else
       return GetFirstItemBox(++aOffset, 0);
   }

layout/xul/nsListBoxBodyFrame.h

@@ -185,7 +185,7 @@ protected:
   nsCOMPtr<nsPIBoxObject> mBoxObject;
 
   // frame markers
-  AutoWeakFrame mTopFrame;
+  WeakFrame mTopFrame;
   nsIFrame* mBottomFrame;
   nsIFrame* mLinkupFrame;
 

layout/xul/nsMenuFrame.cpp

@@ -138,7 +138,7 @@ public:
     return NS_OK;
   }
 protected:
-  AutoWeakFrame       mFrame;
+  WeakFrame         mFrame;
   nsCOMPtr<nsIAtom> mAttr;
 };
 

layout/xul/nsProgressMeterFrame.cpp

@@ -31,7 +31,7 @@ public:
 
   NS_DECL_NSIRUNNABLE
 
-  AutoWeakFrame mWeakFrame;
+  WeakFrame mWeakFrame;
   nsIPresShell::IntrinsicDirty mIntrinsicDirty;
   nsFrameState mBitToAdd;
 };
@@ -100,7 +100,7 @@ public:
     delete this;
   }
 
-  AutoWeakFrame mWeakFrame;
+  WeakFrame mWeakFrame;
 };
 
 NS_IMETHODIMP

layout/xul/nsTextBoxFrame.cpp

@@ -187,11 +187,11 @@ public:
         delete this;
     }
 
-    AutoWeakFrame mWeakFrame;
+    WeakFrame mWeakFrame;
 };
 
 bool
-nsTextBoxFrame::UpdateAccesskey(AutoWeakFrame& aWeakThis)
+nsTextBoxFrame::UpdateAccesskey(WeakFrame& aWeakThis)
 {
     nsAutoString accesskey;
     nsCOMPtr<nsIDOMXULLabelElement> labelElement = do_QueryInterface(mContent);

layout/xul/nsTextBoxFrame.h

@@ -71,7 +71,7 @@ protected:
   friend class nsDisplayXULTextBox;
   // Should be called only by nsAsyncAccesskeyUpdate.
   // Returns true if accesskey was updated.
-  bool UpdateAccesskey(AutoWeakFrame& aWeakThis);
+  bool UpdateAccesskey(WeakFrame& aWeakThis);
   void UpdateAccessTitle();
   void UpdateAccessIndex();
 

layout/xul/nsXULPopupManager.cpp

@@ -1263,12 +1263,11 @@ void
 nsXULPopupManager::HidePopupsInList(const nsTArray<nsMenuPopupFrame *> &aFrames)
 {
   // Create a weak frame list. This is done in a separate array with the
-  // right capacity predetermined, otherwise the array would get resized and
-  // move the weak frame pointers around.
-  nsTArray<AutoWeakFrame> weakPopups(aFrames.Length());
+  // right capacity predetermined to avoid multiple allocations.
+  nsTArray<WeakFrame> weakPopups(aFrames.Length());
   uint32_t f;
   for (f = 0; f < aFrames.Length(); f++) {
-    AutoWeakFrame* wframe = weakPopups.AppendElement();
+    WeakFrame* wframe = weakPopups.AppendElement();
     if (wframe)
       *wframe = aFrames[f];
   }

layout/xul/tree/nsTreeBodyFrame.cpp

@@ -4906,7 +4906,7 @@ public:
     return NS_OK;
   }
 private:
-  AutoWeakFrame mFrame;
+  WeakFrame mFrame;
 };
 
 bool