Oilpan: promptly dispose style resolvers upon clearing.

third_party/WebKit/Source/core/dom/TreeScope.cpp

 /*
  * 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 138 matching lines @@
 ScopedStyleResolver& TreeScope::ensureScopedStyleResolver()
 {
     RELEASE_ASSERT(this);
     if (!m_scopedStyleResolver)
         m_scopedStyleResolver = ScopedStyleResolver::create(*this);
     return *m_scopedStyleResolver;
 }
 
 void TreeScope::clearScopedStyleResolver()
 {
+#if ENABLE(OILPAN)
+    if (m_scopedStyleResolver) {
+        // See StyleEngine::clearResolver() for the motivation for
+        // this explicit disposal step. Same applies for ScopedStyleResolvers.
+        m_scopedStyleResolver->dispose();
+    }
+#endif
     m_scopedStyleResolver.clear();
 }
 
 Element* TreeScope::getElementById(const AtomicString& elementId) const
 {
     if (elementId.isEmpty())
         return 0;
     if (!m_elementsById)
         return 0;
     return m_elementsById->getElementById(elementId, this);
@@ skipping 411 matching lines @@
     visitor->trace(m_parentTreeScope);
     visitor->trace(m_idTargetObserverRegistry);
     visitor->trace(m_selection);
     visitor->trace(m_elementsById);
     visitor->trace(m_imageMapsByName);
     visitor->trace(m_labelsByForAttribute);
     visitor->trace(m_scopedStyleResolver);
 }
 
 } // namespace blink