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 e4efc64407a816e1404402dc5e8df703ba5bf3d7..160ada8c3bd27f58d257f68327a921e1e6f299f2 100644
--- a/Source/core/rendering/RenderLayerBacking.h
+++ b/Source/core/rendering/RenderLayerBacking.h
@@ -98,6 +98,7 @@ public:
     GraphicsLayer* scrollingContentsLayer() const { return m_scrollingContentsLayer.get(); }
 
     bool hasMaskLayer() const { return m_maskLayer != 0; }
+    bool hasBorderRadiusLayer() const { return m_borderRadiusLayer; }
 
     GraphicsLayer* parentForSublayers() const;
     GraphicsLayer* childForSuperlayers() const;
@@ -185,6 +186,7 @@ private:
     bool updateForegroundLayer(bool needsForegroundLayer);
     bool updateBackgroundLayer(bool needsBackgroundLayer);
     bool updateMaskLayer(bool needsMaskLayer);
+    bool updateBorderRadiusLayer(bool needsBorderRadiusLayer);
     bool requiresHorizontalScrollbarLayer() const { return m_owningLayer->horizontalScrollbar(); }
     bool requiresVerticalScrollbarLayer() const { return m_owningLayer->verticalScrollbar(); }
     bool requiresScrollCornerLayer() const { return !m_owningLayer->scrollCornerAndResizerRect().isEmpty(); }
@@ -247,6 +249,7 @@ private:
     OwnPtr<GraphicsLayer> m_backgroundLayer; // Only used in cases where we need to draw the background separately.
     OwnPtr<GraphicsLayer> m_childContainmentLayer; // Only used if we have clipping on a stacking context with compositing children, or if the layer has a tile cache.
     OwnPtr<GraphicsLayer> m_maskLayer; // Only used if we have a mask.
+    OwnPtr<GraphicsLayer> m_borderRadiusLayer; // Only used if we have rounded border on canvas, video or embedded objects.
 
     OwnPtr<GraphicsLayer> m_layerForHorizontalScrollbar;
     OwnPtr<GraphicsLayer> m_layerForVerticalScrollbar;