Use LocalStyleChange for classes in rightmost compound selector.

Source/core/css/RuleFeature.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 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.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 102 matching lines @@
         void add(const FeatureMetadata& other);
         void clear();
 
         bool usesFirstLineRules;
         bool foundSiblingSelector;
         unsigned maxDirectAdjacentSelectors;
         HashSet<AtomicString> idsInRules;
         HashSet<AtomicString> attrsInRules;
     };
 
-    enum SelectorFeatureCollectionMode {
-        ProcessClasses,
-        DontProcessClasses
+    enum InvalidationSetMode {
+        AddFeatures,
+        UseLocalStyleChange,
+        UseSubtreeStyleChange
     };
 
-    void collectFeaturesFromSelector(const CSSSelector&, FeatureMetadata&, SelectorFeatureCollectionMode processClasses);
-    void collectFeaturesFromSelectorList(const CSSSelectorList*, FeatureMetadata&, SelectorFeatureCollectionMode processClasses);
+    static InvalidationSetMode supportsClassDescendantInvalidation(const CSSSelector&);
+
+    void collectFeaturesFromSelector(const CSSSelector&, FeatureMetadata&, InvalidationSetMode);
+    void collectFeaturesFromSelectorList(const CSSSelectorList*, FeatureMetadata&, InvalidationSetMode);
 
     DescendantInvalidationSet& ensureClassInvalidationSet(const AtomicString& className);
-    bool updateClassInvalidationSets(const CSSSelector&);
+    InvalidationSetMode updateClassInvalidationSets(const CSSSelector&);
 
     void addClassToInvalidationSet(const AtomicString& className, Element*);
 
     bool invalidateStyleForClassChange(Element*, Vector<AtomicString>&, bool foundInvalidationSet);
     bool invalidateStyleForClassChangeOnChildren(Element*, Vector<AtomicString>& invalidationClasses, bool foundInvalidationSet);
 
     InvalidationList& ensurePendingInvalidationList(Element*);
 
     FeatureMetadata m_metadata;
     InvalidationSetMap m_classInvalidationSets;
     PendingInvalidationMap m_pendingInvalidationMap;
 
     bool m_targetedStyleRecalcEnabled;
 };
 
 } // namespace WebCore
 
 #endif // RuleFeature_h