Large canvas does not honor containing div's border radius

Source/core/platform/graphics/GraphicsLayerClient.h

 /*
  * Copyright (C) 2009 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 25 matching lines @@
 class IntPoint;
 class IntRect;
 class TransformationMatrix;
 
 enum GraphicsLayerPaintingPhaseFlags {
     GraphicsLayerPaintBackground = (1 << 0),
     GraphicsLayerPaintForeground = (1 << 1),
     GraphicsLayerPaintMask = (1 << 2),
     GraphicsLayerPaintOverflowContents = (1 << 3),
     GraphicsLayerPaintCompositedScroll = (1 << 4),
+    GraphicsLayerPaintChildClippingMask = (1 << 5),
     GraphicsLayerPaintAllWithOverflowClip = (GraphicsLayerPaintBackground | GraphicsLayerPaintForeground | GraphicsLayerPaintMask)
 };
 typedef unsigned GraphicsLayerPaintingPhase;
 
 enum {
     LayerTreeNormal = 0,
     LayerTreeIncludesDebugInfo = 1 << 0, // Dump extra debugging info like layer addresses.
     LayerTreeIncludesRepaintRects = 1 << 1,
     LayerTreeIncludesPaintingPhases = 1 << 2,
     LayerTreeIncludesRootLayer = 1 << 3
@@ skipping 24 matching lines @@
     // This is executed in GraphicsLayer construction and destruction
     // to verify that we don't create or destroy GraphicsLayers
     // while painting.
     virtual void verifyNotPainting() { }
 #endif
 };
 
 } // namespace WebCore
 
 #endif // GraphicsLayerClient_h