Large canvas does not honor containing div's border radius

Source/core/rendering/RenderLayerBacking.h

Index: Source/core/rendering/RenderLayerBacking.h
diff --git a/Source/core/rendering/RenderLayerBacking.h b/Source/core/rendering/RenderLayerBacking.h
index 6285afd8461769980fc025035ed4b5e5c0454369..5e2429645cafb722d4b0c6936c0090c709486637 100644
--- a/Source/core/rendering/RenderLayerBacking.h
+++ b/Source/core/rendering/RenderLayerBacking.h
@@ -111,6 +111,7 @@ public:
     GraphicsLayer* scrollingContentsLayer() const { return m_scrollingContentsLayer.get(); }
 
     bool hasMaskLayer() const { return m_maskLayer != 0; }
+    bool hasChildClippingMaskLayer() const { return m_childClippingMaskLayer; }
 
     GraphicsLayer* parentForSublayers() const;
     GraphicsLayer* childForSuperlayers() const;
@@ -197,6 +198,7 @@ private:
     bool updateForegroundLayer(bool needsForegroundLayer);
     bool updateBackgroundLayer(bool needsBackgroundLayer);
     bool updateMaskLayer(bool needsMaskLayer);
+    bool updateClippingMaskLayers(bool needsChildClippingMaskLayer);
     bool requiresHorizontalScrollbarLayer() const { return m_owningLayer->horizontalScrollbar(); }
     bool requiresVerticalScrollbarLayer() const { return m_owningLayer->verticalScrollbar(); }
     bool requiresScrollCornerLayer() const { return !m_owningLayer->scrollCornerAndResizerRect().isEmpty(); }
@@ -307,6 +309,7 @@ private:
     // the layers above. It's added to m_graphicsLayer as its mask layer (naturally) if
     // we have a mask, and isn't part of the typical hierarchy (it has no children).
     OwnPtr<GraphicsLayer> m_maskLayer; // Only used if we have a mask.
+    OwnPtr<GraphicsLayer> m_childClippingMaskLayer; // Only used if we have to clip child layers or accelerated contents with border radius or clip-path.
 
     // There are two other (optional) layers whose painting is managed by the RenderLayerBacking,
     // but whose position in the hierarchy is maintained by the RenderLayerCompositor. These