Implement style invalidation tree walk for targeted style recalc upon class change.

Source/core/dom/Document.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
@@ skipping 1040 matching lines @@
 
 private:
     friend class Node;
     friend class IgnoreDestructiveWriteCountIncrementer;
 
     ScriptedAnimationController& ensureScriptedAnimationController();
     virtual SecurityContext& securityContext() OVERRIDE FINAL { return *this; }
     virtual EventQueue* eventQueue() const OVERRIDE FINAL;
 
     void updateDistributionIfNeeded();
+    void updateStyleInvalidationIfNeeded();
 
     void updateUseShadowTrees();
 
     void unscheduleStyleRecalc();
 
     void detachParser();
 
     virtual bool isDocument() const OVERRIDE FINAL { return true; }
 
     virtual void childrenChanged(bool changedByParser = false, Node* beforeChange = 0, Node* afterChange = 0, int childCountDelta = 0) OVERRIDE;
@@ skipping 304 matching lines @@
 inline bool Node::isDocumentNode() const
 {
     return this == document();
 }
 
 Node* eventTargetNodeForDocument(Document*);
 
 } // namespace WebCore
 
 #endif // Document_h