Backed out changeset c2b8107d8468 (bug 1321412)

layout/painting/nsDisplayList.cpp

@@ -5743,7 +5743,7 @@ nsDisplayTransform::nsDisplayTransform(nsDisplayListBuilder* aBuilder,
   , mNoExtendContext(false)
   , mIsTransformSeparator(false)
   , mTransformPreserves3DInited(false)
-  , mAllowAsyncAnimation(false)
+  , mIsFullyVisible(false)
 {
   MOZ_COUNT_CTOR(nsDisplayTransform);
   MOZ_ASSERT(aFrame, "Must have a frame!");
@@ -5799,7 +5799,7 @@ nsDisplayTransform::nsDisplayTransform(nsDisplayListBuilder* aBuilder,
                                        nsIFrame *aFrame, nsDisplayList *aList,
                                        const nsRect& aChildrenVisibleRect,
                                        uint32_t aIndex,
-                                       bool aAllowAsyncAnimation)
+                                       bool aIsFullyVisible)
   : nsDisplayItem(aBuilder, aFrame)
   , mStoredList(aBuilder, aFrame, aList)
   , mTransformGetter(nullptr)
@@ -5810,7 +5810,7 @@ nsDisplayTransform::nsDisplayTransform(nsDisplayListBuilder* aBuilder,
   , mNoExtendContext(false)
   , mIsTransformSeparator(false)
   , mTransformPreserves3DInited(false)
-  , mAllowAsyncAnimation(aAllowAsyncAnimation)
+  , mIsFullyVisible(aIsFullyVisible)
 {
   MOZ_COUNT_CTOR(nsDisplayTransform);
   MOZ_ASSERT(aFrame, "Must have a frame!");
@@ -5833,7 +5833,7 @@ nsDisplayTransform::nsDisplayTransform(nsDisplayListBuilder* aBuilder,
   , mNoExtendContext(false)
   , mIsTransformSeparator(false)
   , mTransformPreserves3DInited(false)
-  , mAllowAsyncAnimation(false)
+  , mIsFullyVisible(false)
 {
   MOZ_COUNT_CTOR(nsDisplayTransform);
   MOZ_ASSERT(aFrame, "Must have a frame!");
@@ -5857,7 +5857,7 @@ nsDisplayTransform::nsDisplayTransform(nsDisplayListBuilder* aBuilder,
   , mNoExtendContext(false)
   , mIsTransformSeparator(true)
   , mTransformPreserves3DInited(false)
-  , mAllowAsyncAnimation(false)
+  , mIsFullyVisible(false)
 {
   MOZ_COUNT_CTOR(nsDisplayTransform);
   MOZ_ASSERT(aFrame, "Must have a frame!");
@@ -6223,7 +6223,7 @@ nsDisplayOpacity::CanUseAsyncAnimations(nsDisplayListBuilder* aBuilder)
 bool
 nsDisplayTransform::CanUseAsyncAnimations(nsDisplayListBuilder* aBuilder)
 {
-  return mAllowAsyncAnimation;
+  return mIsFullyVisible;
 }
 
 /* static */ bool
@@ -6400,7 +6400,7 @@ already_AddRefed<Layer> nsDisplayTransform::BuildLayer(nsDisplayListBuilder *aBu
   nsDisplayListBuilder::AddAnimationsAndTransitionsToLayer(container, aBuilder,
                                                            this, mFrame,
                                                            eCSSProperty_transform);
-  if (mAllowAsyncAnimation && MayBeAnimated(aBuilder)) {
+  if (mIsFullyVisible && MayBeAnimated(aBuilder)) {
     // Only allow async updates to the transform if we're an animated layer, since that's what
     // triggers us to set the correct AGR in the constructor and makes sure FrameLayerBuilder
     // won't compute occlusions for this layer.

layout/painting/nsDisplayList.h

@@ -4077,7 +4077,7 @@ public:
    */
   nsDisplayTransform(nsDisplayListBuilder* aBuilder, nsIFrame *aFrame,
                      nsDisplayList *aList, const nsRect& aChildrenVisibleRect,
-                     uint32_t aIndex = 0, bool aAllowAsyncAnimation = false);
+                     uint32_t aIndex = 0, bool aIsFullyVisible = false);
   nsDisplayTransform(nsDisplayListBuilder* aBuilder, nsIFrame *aFrame,
                      nsDisplayItem *aItem, const nsRect& aChildrenVisibleRect,
                      uint32_t aIndex = 0);
@@ -4380,8 +4380,9 @@ private:
   bool mIsTransformSeparator;
   // True if mTransformPreserves3D have been initialized.
   bool mTransformPreserves3DInited;
-  // True if async animation of the transform is allowed.
+  // True if the entire untransformed area has been treated as
-  bool mAllowAsyncAnimation;
+  // visible during display list construction.
+  bool mIsFullyVisible;
 };
 
 /* A display item that applies a perspective transformation to a single