Move computation of 3D descendants to the descendant-dependent flags walk.

third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.cpp

 /*
  * Copyright (C) 2009, 2010, 2011 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 712 matching lines @@
   // Changes to either the internal hierarchy or the mask layer have an impact
   // on painting phases, so we need to update when either are updated.
   if (layerConfigChanged || maskLayerChanged)
     updatePaintingPhases();
 
   updateElementIdAndCompositorMutableProperties();
 
   m_graphicsLayer->setHasWillChangeTransformHint(
       style.hasWillChangeTransformHint());
 
-  m_owningLayer.update3DTransformedDescendantStatus();
   if (style.preserves3D() && style.hasOpacity() &&
       m_owningLayer.has3DTransformedDescendant())
     UseCounter::count(layoutObject->document(),
                       UseCounter::OpacityWithPreserve3DQuirk);
 
   return layerConfigChanged;
 }
 
 static IntRect clipBox(LayoutBox* layoutObject) {
   // TODO(chrishtr): pixel snapping is most likely incorrect here.
@@ skipping 2636 matching lines @@
   } else if (graphicsLayer == m_decorationOutlineLayer.get()) {
     name = "Decoration Layer";
   } else {
     ASSERT_NOT_REACHED();
   }
 
   return name;
 }
 
 }  // namespace blink