Large canvas does not honor containing div's border radius

Source/core/rendering/RenderReplaced.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2000 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2006, 2007 Apple Inc. All rights reserved.
  * Copyright (C) Research In Motion Limited 2011-2012. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
@@ skipping 102 matching lines @@
     LayoutPoint adjustedPaintOffset = paintOffset + location();
     
     if (hasBoxDecorations() && (paintInfo.phase == PaintPhaseForeground || paintInfo.phase == PaintPhaseSelection)) 
         paintBoxDecorations(paintInfo, adjustedPaintOffset);
     
     if (paintInfo.phase == PaintPhaseMask) {
         paintMask(paintInfo, adjustedPaintOffset);
         return;
     }
 
+    if (paintInfo.phase == PaintPhaseBorderRadiusMask && (!hasLayer() || !layer()->hasCompositedBorderRadiusMask()))
+        return;
+
     LayoutRect paintRect = LayoutRect(adjustedPaintOffset, size());
     if ((paintInfo.phase == PaintPhaseOutline || paintInfo.phase == PaintPhaseSelfOutline) && style()->outlineWidth())
         paintOutline(paintInfo, paintRect);
     
-    if (paintInfo.phase != PaintPhaseForeground && paintInfo.phase != PaintPhaseSelection && !canHaveChildren())
+    if (paintInfo.phase != PaintPhaseForeground && paintInfo.phase != PaintPhaseSelection && !canHaveChildren() && paintInfo.phase != PaintPhaseBorderRadiusMask)
         return;
     
     if (!paintInfo.shouldPaintWithinRoot(this))
         return;
     
     bool drawSelectionTint = selectionState() != SelectionNone && !document()->printing();
     if (paintInfo.phase == PaintPhaseSelection) {
         if (selectionState() == SelectionNone)
             return;
         drawSelectionTint = false;
     }
 
     bool completelyClippedOut = false;
     if (style()->hasBorderRadius()) {
         LayoutRect borderRect = LayoutRect(adjustedPaintOffset, size());
 
         if (borderRect.isEmpty())
             completelyClippedOut = true;
         else {
             // Push a clip if we have a border radius, since we want to round the foreground content that gets painted.
             paintInfo.context->save();
             RoundedRect roundedInnerRect = style()->getRoundedInnerBorderFor(paintRect,
                 paddingTop() + borderTop(), paddingBottom() + borderBottom(), paddingLeft() + borderLeft(), paddingRight() + borderRight(), true, true);
             clipRoundedInnerRect(paintInfo.context, paintRect, roundedInnerRect);
         }
     }
 
     if (!completelyClippedOut) {
-        paintReplaced(paintInfo, adjustedPaintOffset);
+        if (paintInfo.phase == PaintPhaseBorderRadiusMask) {
+            paintInfo.context->fillRect(pixelSnappedIntRect(paintRect), Color::black);
+        } else {
+            paintReplaced(paintInfo, adjustedPaintOffset);
+        }
 
         if (style()->hasBorderRadius())
             paintInfo.context->restore();
     }
 
     // The selection tint never gets clipped by border-radius rounding, since we want it to run right up to the edges of
     // surrounding content.
     if (drawSelectionTint) {
         LayoutRect selectionPaintingRect = localSelectionRect();
         selectionPaintingRect.moveBy(adjustedPaintOffset);
         paintInfo.context->fillRect(pixelSnappedIntRect(selectionPaintingRect), selectionBackgroundColor());
     }
 }
 
 bool RenderReplaced::shouldPaint(PaintInfo& paintInfo, const LayoutPoint& paintOffset)
 {
     if (paintInfo.phase != PaintPhaseForeground && paintInfo.phase != PaintPhaseOutline && paintInfo.phase != PaintPhaseSelfOutline 
-            && paintInfo.phase != PaintPhaseSelection && paintInfo.phase != PaintPhaseMask)
+            && paintInfo.phase != PaintPhaseSelection && paintInfo.phase != PaintPhaseMask && paintInfo.phase != PaintPhaseBorderRadiusMask)
         return false;
 
     if (!paintInfo.shouldPaintWithinRoot(this))
         return false;
 
     // if we're invisible or haven't received a layout yet, then just bail.
     if (style()->visibility() != VISIBLE)
         return false;
 
     LayoutPoint adjustedPaintOffset = paintOffset + location();
@@ skipping 396 matching lines @@
     return r;
 }
 
 void RenderReplaced::reportMemoryUsage(MemoryObjectInfo* memoryObjectInfo) const
 {
     MemoryClassInfo info(memoryObjectInfo, this, PlatformMemoryTypes::Rendering);
     RenderBox::reportMemoryUsage(memoryObjectInfo);
 }
 
 }