Implement will-change-based GPU rasterization hint

Source/core/rendering/RenderBox.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003, 2006, 2007 Apple Inc. 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 53 matching lines @@
 
 
 class RenderBox : public RenderBoxModelObject {
 public:
     explicit RenderBox(ContainerNode*);
 
     // hasAutoZIndex only returns true if the element is positioned or a flex-item since
     // position:static elements that are not flex-items get their z-index coerced to auto.
     virtual LayerType layerTypeRequired() const OVERRIDE
     {
-        if (isRoot() || isPositioned() || createsGroup() || hasClipPath() || hasTransform() || hasHiddenBackface() || hasReflection() || style()->specifiesColumns() || !style()->hasAutoZIndex() || style()->hasWillChangeCompositingHint())
+        if (isRoot() || isPositioned() || createsGroup() || hasClipPath() || hasTransform() || hasHiddenBackface() || hasReflection() || style()->specifiesColumns() || !style()->hasAutoZIndex() || style()->hasWillChangeCompositingHint() || style()->hasWillChangeCompositingHint())

[abarth-chromium, 2014/03/07 16:04:39]

Why do we need this twice?  Maybe you meant hasWillChangeGpuRasterizationHint ?

[ajuma, 2014/03/07 17:03:41]

Indeed, thanks for catching that!

             return NormalLayer;
         if (hasOverflowClip())
             return OverflowClipLayer;
 
         return NoLayer;
     }
 
     virtual bool backgroundIsKnownToBeOpaqueInRect(const LayoutRect& localRect) const OVERRIDE;
 
     // Use this with caution! No type checking is done!
@@ skipping 689 matching lines @@
         if (UNLIKELY(inlineBoxWrapper() != 0))
             deleteLineBoxWrapper();
     }
 
     ensureRareData().m_inlineBoxWrapper = boxWrapper;
 }
 
 } // namespace WebCore
 
 #endif // RenderBox_h