Add infrastructure for partial layouts

Source/core/rendering/RenderFlowThread.h

 /*
  * Copyright (C) 2011 Adobe Systems Incorporated. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1. Redistributions of source code must retain the above
  *    copyright notice, this list of conditions and the following
  *    disclaimer.
@@ skipping 250 matching lines @@
 
     bool m_regionsInvalidated : 1;
     bool m_regionsHaveUniformLogicalWidth : 1;
     bool m_regionsHaveUniformLogicalHeight : 1;
     bool m_hasRegionsWithStyling : 1;
     bool m_dispatchRegionLayoutUpdateEvent : 1;
     bool m_dispatchRegionOversetChangeEvent : 1;
     bool m_pageLogicalSizeChanged : 1;
     bool m_inConstrainedLayoutPhase : 1;
     bool m_needsTwoPhasesLayout : 1;
+
+private:
+    virtual bool supportsPartialLayout() const OVERRIDE { return false; }
+
 };
 
 inline RenderFlowThread* toRenderFlowThread(RenderObject* object)
 {
     ASSERT_WITH_SECURITY_IMPLICATION(!object || object->isRenderFlowThread());
     return static_cast<RenderFlowThread*>(object);
 }
 
 inline const RenderFlowThread* toRenderFlowThread(const RenderObject* object)
 {
@@ skipping 21 matching lines @@
 };
 
 template <> struct ValueToString<RenderRegion*> {
     static String string(const RenderRegion* value) { return String::format("%p", value); }
 };
 #endif
 
 } // namespace WebCore
 
 #endif // RenderFlowThread_h