Large canvas does not honor containing div's border radius

Source/core/platform/graphics/GraphicsLayer.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 232 matching lines @@
     void addChildAtIndex(GraphicsLayer*, int index);
     void addChildAbove(GraphicsLayer*, GraphicsLayer* sibling);
     void addChildBelow(GraphicsLayer*, GraphicsLayer* sibling);
     bool replaceChild(GraphicsLayer* oldChild, GraphicsLayer* newChild);
 
     void removeAllChildren();
     void removeFromParent();
 
     GraphicsLayer* maskLayer() const { return m_maskLayer; }
     void setMaskLayer(GraphicsLayer*);
+
+    GraphicsLayer* borderRadiusLayer() const { return m_borderRadiusLayer; }
+    void setBorderRadiusLayer(GraphicsLayer*);
     
     // The given layer will replicate this layer and its children; the replica renders behind this layer.
     void setReplicatedByLayer(GraphicsLayer*);
     // Whether this layer is being replicated by another layer.
     bool isReplicated() const { return m_replicaLayer; }
     // The layer that replicates this layer (if any).
     GraphicsLayer* replicaLayer() const { return m_replicaLayer; }
 
     const FloatPoint& replicatedLayerPosition() const { return m_replicatedLayerPosition; }
     void setReplicatedLayerPosition(const FloatPoint& p) { m_replicatedLayerPosition = p; }
@@ skipping 263 matching lines @@
     bool m_showDebugBorder : 1;
     bool m_showRepaintCounter : 1;
     
     GraphicsLayerPaintingPhase m_paintingPhase;
     CompositingCoordinatesOrientation m_contentsOrientation; // affects orientation of layer contents
 
     Vector<GraphicsLayer*> m_children;
     GraphicsLayer* m_parent;
 
     GraphicsLayer* m_maskLayer; // Reference to mask layer. We don't own this.
+    GraphicsLayer* m_borderRadiusLayer; // Reference to border radius mask layer. We don't own this.
 
     GraphicsLayer* m_replicaLayer; // A layer that replicates this layer. We only allow one, for now.
                                    // The replica is not parented; this is the primary reference to it.
     GraphicsLayer* m_replicatedLayer; // For a replica layer, a reference to the original layer.
     FloatPoint m_replicatedLayerPosition; // For a replica layer, the position of the replica.
 
     IntRect m_contentsRect;
 
     int m_repaintCount;
 
@@ skipping 26 matching lines @@
 
 
 } // namespace WebCore
 
 #ifndef NDEBUG
 // Outside the WebCore namespace for ease of invocation from gdb.
 void showGraphicsLayerTree(const WebCore::GraphicsLayer* layer);
 #endif
 
 #endif // GraphicsLayer_h