Bug 815671 part 7. Fixes to layout code to not copy arrays implicitly. r=roc

layout/generic/nsFlexContainerFrame.cpp

@@ -1296,26 +1296,23 @@ nsFlexContainerFrame::ResolveFlexibleLengths(
 #endif // DEBUG
 }
 
-const nsTArray<SortableFrame>
-BuildSortedChildArray(const nsFrameList& aChildren)
+void
+BuildSortedChildArray(const nsFrameList& aChildren,
+		      nsTArray<SortableFrame>& aSortedChildren)
 {
-  // NOTE: To benefit from Return Value Optimization, we must only return
-  // this value:
-  nsTArray<SortableFrame> sortedChildArray(aChildren.GetLength());
+  aSortedChildren.SetCapacity(aChildren.GetLength());
 
   // Throw all our children in the array...
   uint32_t indexInFrameList = 0;
   for (nsFrameList::Enumerator e(aChildren); !e.AtEnd(); e.Next()) {
     int32_t orderValue = e.get()->GetStylePosition()->mOrder;
-    sortedChildArray.AppendElement(SortableFrame(e.get(), orderValue,
-                                                 indexInFrameList));
+    aSortedChildren.AppendElement(SortableFrame(e.get(), orderValue,
+						indexInFrameList));
     indexInFrameList++;
   }
 
   // ... and sort (by 'order' property)
-  sortedChildArray.Sort();
-
-  return sortedChildArray;
+  aSortedChildren.Sort();
 }
 
 MainAxisPositionTracker::
@@ -1787,7 +1784,8 @@ nsFlexContainerFrame::GenerateFlexItems(
   MOZ_ASSERT(aFlexItems.IsEmpty(), "Expecting outparam to start out empty");
 
   // Sort by 'order' property:
-  const nsTArray<SortableFrame> sortedChildren = BuildSortedChildArray(mFrames);
+  nsTArray<SortableFrame> sortedChildren;
+  BuildSortedChildArray(mFrames, sortedChildren);
 
   // Build list of unresolved flex items:
 

layout/ipc/RenderFrameParent.cpp

@@ -881,7 +881,7 @@ RenderFrameParent::TriggerRepaint()
 ShadowLayersParent*
 RenderFrameParent::GetShadowLayers() const
 {
-  const nsTArray<PLayersParent*>& shadowParents = ManagedPLayersParent();
+  const InfallibleTArray<PLayersParent*>& shadowParents = ManagedPLayersParent();
   NS_ABORT_IF_FALSE(shadowParents.Length() <= 1,
                     "can only support at most 1 ShadowLayersParent");
   return (shadowParents.Length() == 1) ?

layout/style/nsCSSRules.h

@@ -354,7 +354,7 @@ class nsCSSKeyframeRule MOZ_FINAL : public mozilla::css::Rule,
 {
 public:
   // WARNING: Steals the contents of aKeys *and* aDeclaration
-  nsCSSKeyframeRule(nsTArray<float> aKeys,
+  nsCSSKeyframeRule(InfallibleTArray<float>& aKeys,
                     nsAutoPtr<mozilla::css::Declaration> aDeclaration)
     : mDeclaration(aDeclaration)
   {
@@ -392,7 +392,7 @@ public:
   void DoGetKeyText(nsAString &aKeyText) const;
 
 private:
-  nsAutoTArray<float, 1>                     mKeys;
+  nsTArray<float>                            mKeys;
   nsAutoPtr<mozilla::css::Declaration>       mDeclaration;
   // lazily created when needed:
   nsRefPtr<nsCSSKeyframeStyleDeclaration>    mDOMDeclaration;