Move viewport unit resolution to style recalc time

Source/core/dom/TreeScope.h

 /*
  * Copyright (C) 2011 Google Inc. All Rights Reserved.
  * Copyright (C) 2012 Apple Inc. 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.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 121 matching lines @@
     void destroyTreeScopeData();
     void clearDocumentScope();
     void setDocumentScope(Document* document)
     {
         ASSERT(document);
         m_documentScope = document;
     }
 
     bool hasGuardRefCount() const { return m_guardRefCount; }
 
+    void setNeedsStyleRecalcForViewportUnits();
+
 private:
     TreeScope();
 
     virtual void dispose() { }
 
     int refCount() const;
 #if SECURITY_ASSERT_ENABLED
     bool deletionHasBegun();
     void beginDeletion();
 #else
@@ skipping 34 matching lines @@
 inline bool operator!=(const TreeScope& a, const TreeScope& b) { return !(a == b); }
 inline bool operator!=(const TreeScope& a, const TreeScope* b) { return !(a == b); }
 inline bool operator!=(const TreeScope* a, const TreeScope& b) { return !(a == b); }
 
 RenderObject* rendererFromPoint(Document*, int x, int y, LayoutPoint* localPoint = 0);
 TreeScope* commonTreeScope(Node*, Node*);
 
 } // namespace WebCore
 
 #endif // TreeScope_h