Skip traversing wholeSubtree subtrees with clean invalidation bits.

Source/core/css/invalidation/StyleInvalidator.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef StyleInvalidator_h
 #define StyleInvalidator_h
 
 #include "platform/heap/Handle.h"
 
 namespace WebCore {
@@ skipping 25 matching lines @@
 
     struct RecursionData {
         RecursionData()
             : m_invalidateCustomPseudo(false)
             , m_wholeSubtreeInvalid(false)
             , m_treeBoundaryCrossing(false)
         { }
 
         void pushInvalidationSet(const DescendantInvalidationSet&);
         bool matchesCurrentInvalidationSets(Element&);
-        bool hasInvalidationSets() const { return m_invalidationSets.size(); }
+        bool hasInvalidationSets() const { return !wholeSubtreeInvalid() && m_invalidationSets.size(); }
 
         bool wholeSubtreeInvalid() const { return m_wholeSubtreeInvalid; }
         void setWholeSubtreeInvalid() { m_wholeSubtreeInvalid = true; }
 
         bool treeBoundaryCrossing() const { return m_treeBoundaryCrossing; }
 
         typedef Vector<const DescendantInvalidationSet*, 16> InvalidationSets;
         InvalidationSets m_invalidationSets;
         bool m_invalidateCustomPseudo;
         bool m_wholeSubtreeInvalid;
@@ skipping 30 matching lines @@
 
     InvalidationList& ensurePendingInvalidationList(Element&);
 
     PendingInvalidationMap m_pendingInvalidationMap;
     RecursionData m_recursionData;
 };
 
 } // namespace WebCore
 
 #endif // StyleInvalidator_h