Update composited layer size if overflow from children requires it

third_party/WebKit/Source/core/layout/LayoutBlock.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2007 David Smith (catfish.man@gmail.com)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) Research In Motion Limited 2010. 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
@@ skipping 420 matching lines @@
         if (isHorizontalWritingMode())
             rectToApply = LayoutRect(clientRect.x(), clientRect.y(), LayoutUnit(1), (oldClientAfterEdge - clientRect.y()).clampNegativeToZero());
         else
             rectToApply = LayoutRect(clientRect.x(), clientRect.y(), (oldClientAfterEdge - clientRect.x()).clampNegativeToZero(), LayoutUnit(1));
         addLayoutOverflow(rectToApply);
         if (hasOverflowModel())
             m_overflow->setLayoutClientAfterEdge(oldClientAfterEdge);
     }
 
     addVisualEffectOverflow();
+    addVisualOverflowFromTheme();
 
-    addVisualOverflowFromTheme();
+    // An enclosing composited layer will need to update its bounds if we now overflow it.
+    PaintLayer* layer = enclosingLayer();
+    if (!needsLayout() && layer->hasCompositedLayerMapping() && !layer->visualRect().contains(visualOverflowRect()))
+        layer->setNeedsCompositingInputsUpdate();
 }
 
 void LayoutBlock::addOverflowFromBlockChildren()
 {
     for (LayoutBox* child = firstChildBox(); child; child = child->nextSiblingBox()) {
         if (!child->isFloatingOrOutOfFlowPositioned() && !child->isColumnSpanAll())
             addOverflowFromChild(child);
     }
 }
 
@@ skipping 1395 matching lines @@
         for (TrackedLayoutBoxListHashSet::const_iterator it = positionedDescendantSet->begin(); it != end; ++it) {
             LayoutBox* currBox = *it;
             ASSERT(!currBox->needsLayout());
         }
     }
 }
 
 #endif
 
 } // namespace blink