Early return in RenderLayerCompositor::updateForceCompositingMode.

Source/core/rendering/compositing/RenderLayerCompositor.cpp

 /*
  * Copyright (C) 2009, 2010 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 132 matching lines @@
         destroyRootLayer();
 
     notifyIFramesOfCompositingChange();
 }
 
 void RenderLayerCompositor::updateForceCompositingMode()
 {
     // FIXME: Can settings really be null here?
     if (Settings* settings = m_renderView.document().settings()) {
         bool forceCompositingMode = settings->forceCompositingMode() && m_hasAcceleratedCompositing;
-        if (forceCompositingMode && !isMainFrame())
+        if (forceCompositingMode && !isMainFrame()) {
+            // requiresCompositingForScrollableFrame will return a stale value if the RenderView
+            // needsLayout. Skip updating m_forceCompositingMode here as we'll call back into
+            // this method at the end of layout.
+            if (m_renderView.needsLayout())
+                return;
             forceCompositingMode = m_compositingReasonFinder.requiresCompositingForScrollableFrame();
+        }
         if (forceCompositingMode != m_forceCompositingMode) {
             setCompositingLayersNeedRebuild();
             m_forceCompositingMode = forceCompositingMode;
         }
     }
 }
 
 void RenderLayerCompositor::updateAcceleratedCompositingSettings()
 {
     bool hasAcceleratedCompositing = false;
@@ skipping 1545 matching lines @@
     } else if (graphicsLayer == m_scrollLayer.get()) {
         name = "LocalFrame Scrolling Layer";
     } else {
         ASSERT_NOT_REACHED();
     }
 
     return name;
 }
 
 } // namespace WebCore