Add infrastructure for partial layouts

Source/core/rendering/RenderListItem.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2009 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 50 matching lines @@
     virtual void willBeDestroyed();
 
     virtual void insertedIntoTree() OVERRIDE;
     virtual void willBeRemovedFromTree() OVERRIDE;
 
     virtual bool isEmpty() const;
     virtual void paint(PaintInfo&, const LayoutPoint&);
 
     virtual void layout();
 
+    virtual bool supportsPartialLayout() const OVERRIDE { return false; }
+
     void positionListMarker();
 
     virtual void styleDidChange(StyleDifference, const RenderStyle* oldStyle);
 
     virtual bool requiresForcedStyleRecalcPropagation() const { return true; }
 
     virtual void addOverflowFromChildren();
 
     void updateMarkerLocation();
     inline int calcValue() const;
@@ skipping 14 matching lines @@
     ASSERT_WITH_SECURITY_IMPLICATION(!object || object->isListItem());
     return static_cast<RenderListItem*>(object);
 }
 
 // This will catch anyone doing an unnecessary cast.
 void toRenderListItem(const RenderListItem*);
 
 } // namespace WebCore
 
 #endif // RenderListItem_h