Large canvas does not honor containing div's border radius

Source/core/rendering/RenderLayer.cpp

Index: Source/core/rendering/RenderLayer.cpp
diff --git a/Source/core/rendering/RenderLayer.cpp b/Source/core/rendering/RenderLayer.cpp
index c56125a15a178687d2ac0e647d4773554b8e1124..987fcab82d49a38b7fc2df277a2182ce783c327d 100644
--- a/Source/core/rendering/RenderLayer.cpp
+++ b/Source/core/rendering/RenderLayer.cpp
@@ -3801,6 +3801,11 @@ void RenderLayer::paintLayerContents(GraphicsContext* context, const LayerPainti
         paintMaskForFragments(layerFragments, context, localPaintingInfo, paintingRootForRenderer);
     }
 
+    if ((localPaintFlags & PaintLayerPaintingCompositingBorderRadiusMaskPhase) && renderer()->style()->hasBorderRadius() && shouldPaintContent && !selectionOnly) {
+        // Paint the border radius mask for the fragments.
+        paintMaskForFragments(layerFragments, context, localPaintingInfo, paintingRootForRenderer, PaintPhaseBorderRadiusMask);
+    }
+
     // End our transparency layer
     if (haveTransparency && m_usedTransparency && !m_paintingInsideReflection) {
         context->endTransparencyLayer();
@@ -4080,7 +4085,7 @@ void RenderLayer::paintOutlineForFragments(const LayerFragments& layerFragments,
 }
 
 void RenderLayer::paintMaskForFragments(const LayerFragments& layerFragments, GraphicsContext* context, const LayerPaintingInfo& localPaintingInfo,
-    RenderObject* paintingRootForRenderer)
+    RenderObject* paintingRootForRenderer, PaintPhase paintPhase)
 {
     for (size_t i = 0; i < layerFragments.size(); ++i) {
         const LayerFragment& fragment = layerFragments.at(i);
@@ -4092,7 +4097,7 @@ void RenderLayer::paintMaskForFragments(const LayerFragments& layerFragments, Gr
         
         // Paint the mask.
         // FIXME: Eventually we will collect the region from the fragment itself instead of just from the paint info.
-        PaintInfo paintInfo(context, pixelSnappedIntRect(fragment.backgroundRect.rect()), PaintPhaseMask, PaintBehaviorNormal, paintingRootForRenderer, localPaintingInfo.region, 0, 0, localPaintingInfo.rootLayer->renderer());
+        PaintInfo paintInfo(context, pixelSnappedIntRect(fragment.backgroundRect.rect()), paintPhase, PaintBehaviorNormal, paintingRootForRenderer, localPaintingInfo.region, 0, 0, localPaintingInfo.rootLayer->renderer());
         renderer()->paint(paintInfo, toPoint(fragment.layerBounds.location() - renderBoxLocation() + localPaintingInfo.subPixelAccumulation));
         
         if (localPaintingInfo.clipToDirtyRect)
@@ -5419,6 +5424,11 @@ bool RenderLayer::hasCompositedMask() const
     return m_backing && m_backing->hasMaskLayer();
 }
 
+bool RenderLayer::hasCompositedBorderRadiusMask() const
+{
+    return m_backing && m_backing->hasBorderRadiusLayer();
+}
+
 GraphicsLayer* RenderLayer::layerForScrolling() const
 {
     return m_backing ? m_backing->scrollingContentsLayer() : 0;