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

Source/core/dom/Node.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  *
  * 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
@@ skipping 353 matching lines @@
     void clearChildNeedsStyleRecalc() { clearFlag(ChildNeedsStyleRecalcFlag); }
 
     void setNeedsStyleRecalc(StyleChangeType = SubtreeStyleChange, StyleChangeSource = StyleChangeFromCSS);
     void clearNeedsStyleRecalc();
 
     bool childNeedsDistributionRecalc() const { return getFlag(ChildNeedsDistributionRecalc); }
     void setChildNeedsDistributionRecalc()  { setFlag(ChildNeedsDistributionRecalc); }
     void clearChildNeedsDistributionRecalc()  { clearFlag(ChildNeedsDistributionRecalc); }
     void markAncestorsWithChildNeedsDistributionRecalc();
 
+    bool childNeedsStyleInvalidation() const { return getFlag(ChildNeedsStyleInvalidation); }
+    void setChildNeedsStyleInvalidation()  { setFlag(ChildNeedsStyleInvalidation); }
+    void clearChildNeedsStyleInvalidation()  { clearFlag(ChildNeedsStyleInvalidation); }
+    void markAncestorsWithChildNeedsStyleInvalidation();
+
     void recalcDistribution();
 
     bool shouldNotifyRendererWithIdenticalStyles() const { return getFlag(NotifyRendererWithIdenticalStyles); }
 
     void setIsLink(bool f);
 
     void setInNamedFlow() { setFlag(InNamedFlowFlag); }
     void clearInNamedFlow() { clearFlag(InNamedFlowFlag); }
 
     bool hasScopedHTMLStyleChild() const { return getFlag(HasScopedHTMLStyleChildFlag); }
@@ skipping 323 matching lines @@
         HasEventTargetDataFlag = 1 << 22,
         V8CollectableDuringMinorGCFlag = 1 << 23,
         IsInsertionPointFlag = 1 << 24,
         IsInShadowTreeFlag = 1 << 25,
 
         NotifyRendererWithIdenticalStyles = 1 << 26,
 
         CustomElement = 1 << 27,
         CustomElementUpgraded = 1 << 28,
 
+        ChildNeedsStyleInvalidation = 1 << 29,
+
         DefaultNodeFlags = IsParsingChildrenFinishedFlag | ChildNeedsStyleRecalcFlag | NeedsReattachStyleChange
     };
 
-    // 4 bits remaining.
+    // 2 bits remaining.
 
     bool getFlag(NodeFlags mask) const { return m_nodeFlags & mask; }
     void setFlag(bool f, NodeFlags mask) const { m_nodeFlags = (m_nodeFlags & ~mask) | (-(int32_t)f & mask); }
     void setFlag(NodeFlags mask) const { m_nodeFlags |= mask; }
     void clearFlag(NodeFlags mask) const { m_nodeFlags &= ~mask; }
 
 protected:
     enum ConstructionType {
         CreateOther = DefaultNodeFlags,
         CreateText = DefaultNodeFlags | IsTextFlag,
@@ skipping 171 matching lines @@
 
 } // namespace WebCore
 
 #ifndef NDEBUG
 // Outside the WebCore namespace for ease of invocation from gdb.
 void showTree(const WebCore::Node*);
 void showNodePath(const WebCore::Node*);
 #endif
 
 #endif