Set m_graphicsLayer as fixed position container

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 1497 matching lines @@
     return;
 
   scrollingCoordinator->updateLayerPositionConstraint(&m_owningLayer);
 
   // Page scale is applied as a transform on the root layout view layer. Because
   // the scroll layer is further up in the hierarchy, we need to avoid marking
   // the root layout view layer as a container.
   bool isContainer =
       m_owningLayer.layoutObject()->style()->canContainFixedPositionObjects() &&
       !m_owningLayer.isRootLayer();
-  // FIXME: we should make certain that childForSuperLayers will never be the
-  // m_squashingContainmentLayer here
   scrollingCoordinator->setLayerIsContainerForFixedPositionLayers(
-      childForSuperlayers(), isContainer);
+      m_graphicsLayer.get(), isContainer);
 }
 
 void CompositedLayerMapping::updateInternalHierarchy() {
   // m_foregroundLayer has to be inserted in the correct order with child
   // layers, so it's not inserted here.
   if (m_ancestorClippingLayer)
     m_ancestorClippingLayer->removeAllChildren();
 
   m_graphicsLayer->removeFromParent();
 
@@ skipping 1937 matching lines @@
   } else if (graphicsLayer == m_decorationOutlineLayer.get()) {
     name = "Decoration Layer";
   } else {
     ASSERT_NOT_REACHED();
   }
 
   return name;
 }
 
 }  // namespace blink