Oilpan: move LiveNodeList collections to the heap.

Source/core/dom/NodeRareData.cpp

 /*
  * Copyright (C) 2012 Google 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 40 matching lines @@
         it->value->invalidateCacheForAttribute(attrName);
 
     if (attrName)
         return;
 
     TagCollectionCacheNS::iterator tagCacheEnd = m_tagCollectionCacheNS.end();
     for (TagCollectionCacheNS::iterator it = m_tagCollectionCacheNS.begin(); it != tagCacheEnd; ++it)
         it->value->invalidateCache();
 }
 
+void NodeListsNodeData::trace(Visitor* visitor)
+{
+    visitor->trace(m_childNodeList);
+    visitor->trace(m_atomicNameCaches);
+    visitor->trace(m_tagCollectionCacheNS);
+}
+
 void NodeRareData::traceAfterDispatch(Visitor* visitor)
 {
     visitor->trace(m_mutationObserverData);
+    // Do not keep empty NodeListsNodeData objects around.
+    if (m_nodeLists && m_nodeLists->isEmpty())
+        m_nodeLists.clear();
+    else
+        visitor->trace(m_nodeLists);
 }
 
 void NodeRareData::trace(Visitor* visitor)
 {
     if (m_isElementRareData)
         static_cast<ElementRareData*>(this)->traceAfterDispatch(visitor);
     else
         traceAfterDispatch(visitor);
 }
 
 void NodeRareData::finalizeGarbageCollectedObject()
 {
     RELEASE_ASSERT(!renderer());
     if (m_isElementRareData)
         static_cast<ElementRareData*>(this)->~ElementRareData();
     else
         this->~NodeRareData();
 }
 
 // Ensure the 10 bits reserved for the m_connectedFrameCount cannot overflow
 COMPILE_ASSERT(Page::maxNumberOfFrames < (1 << NodeRareData::ConnectedFrameCountBits), Frame_limit_should_fit_in_rare_data_count);
 
 } // namespace WebCore