Large canvas does not honor containing div's border radius

Source/core/platform/graphics/GraphicsLayer.cpp

Index: Source/core/platform/graphics/GraphicsLayer.cpp
diff --git a/Source/core/platform/graphics/GraphicsLayer.cpp b/Source/core/platform/graphics/GraphicsLayer.cpp
index f7ecd9870041b38f723f51c3be37e46cfd088ae2..bcf6eacdcdbffe8255ca1ec1c5a3b8cd78c1243a 100644
--- a/Source/core/platform/graphics/GraphicsLayer.cpp
+++ b/Source/core/platform/graphics/GraphicsLayer.cpp
@@ -124,6 +124,7 @@ GraphicsLayer::GraphicsLayer(GraphicsLayerClient* client)
     , m_contentsOrientation(CompositingCoordinatesTopDown)
     , m_parent(0)
     , m_maskLayer(0)
+    , m_borderRadiusLayer(0)
     , m_replicaLayer(0)
     , m_replicatedLayer(0)
     , m_repaintCount(0)
@@ -620,6 +621,15 @@ void GraphicsLayer::updateContentsRect()
 
     contentsLayer->setPosition(FloatPoint(m_contentsRect.x(), m_contentsRect.y()));
     contentsLayer->setBounds(IntSize(m_contentsRect.width(), m_contentsRect.height()));
+
+    if (m_borderRadiusLayer) {
+        if (m_borderRadiusLayer->size() != m_contentsRect.size()) {
+            m_borderRadiusLayer->setSize(m_contentsRect.size());
+            m_borderRadiusLayer->setNeedsDisplay();
+        }
+        m_borderRadiusLayer->setPosition(FloatPoint());
+        m_borderRadiusLayer->setOffsetFromRenderer(offsetFromRenderer() + IntSize(m_contentsRect.location().x(), m_contentsRect.location().y()));
+    }
 }
 
 static HashSet<int>* s_registeredLayerSet;
@@ -683,6 +693,8 @@ void GraphicsLayer::setupContentsLayer(WebLayer* contentsLayer)
         // Insert the content layer first. Video elements require this, because they have
         // shadow content that must display in front of the video.
         m_layer->layer()->insertChild(m_contentsLayer, 0);
+        WebLayer* borderWebLayer = m_borderRadiusLayer ? m_borderRadiusLayer->platformLayer() : 0;
+        m_contentsLayer->setMaskLayer(borderWebLayer);
     }
     updateNames();
 }
@@ -892,6 +904,10 @@ void GraphicsLayer::dumpProperties(TextStream& ts, int indent, LayerTreeFlags fl
             writeIndent(ts, indent + 2);
             ts << "GraphicsLayerPaintMask\n";
         }
+        if (paintingPhase() & GraphicsLayerPaintBorderRadiusMask) {
+            writeIndent(ts, indent + 2);
+            ts << "GraphicsLayerPaintBorderRadiusMask\n";
+        }
         if (paintingPhase() & GraphicsLayerPaintOverflowContents) {
             writeIndent(ts, indent + 2);
             ts << "GraphicsLayerPaintOverflowContents\n";
@@ -932,6 +948,7 @@ void GraphicsLayer::reportMemoryUsage(MemoryObjectInfo* memoryObjectInfo) const
     info.addMember(m_children, "children");
     info.addMember(m_parent, "parent");
     info.addMember(m_maskLayer, "maskLayer");
+    info.addMember(m_borderRadiusLayer, "borderRadiusLayer");
     info.addMember(m_replicaLayer, "replicaLayer");
     info.addMember(m_replicatedLayer, "replicatedLayer");
     info.ignoreMember(m_client);
@@ -1070,6 +1087,18 @@ void GraphicsLayer::setMaskLayer(GraphicsLayer* maskLayer)
     m_layer->layer()->setMaskLayer(maskWebLayer);
 }
 
+void GraphicsLayer::setBorderRadiusLayer(GraphicsLayer* borderRadiusLayer)
+{
+    if (borderRadiusLayer == m_borderRadiusLayer)
+        return;
+
+    m_borderRadiusLayer = borderRadiusLayer;
+    WebLayer* borderRadiusWebLayer = m_borderRadiusLayer ? m_borderRadiusLayer->platformLayer() : 0;
+    if (hasContentsLayer())
+        contentsLayer()->setMaskLayer(borderRadiusWebLayer);
+    updateContentsRect();
+}
+
 void GraphicsLayer::setBackfaceVisibility(bool visible)
 {
     m_backfaceVisibility = visible;