Have LiveNodeListBase::ownerNode() return a reference

Source/core/dom/NodeRareData.h

 /*
  * Copyright (C) 2008, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2008 David Smith <catfish.man@gmail.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
  * 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 183 matching lines @@
         : m_childNodeList(0)
     { }
 
     std::pair<unsigned char, StringImpl*> namedNodeListKey(CollectionType type, const AtomicString& name)
     {
         // Holding the raw StringImpl is safe because |name| is retained by the NodeList and the NodeList
         // is reponsible for removing itself from the cache on deletion.
         return std::pair<unsigned char, StringImpl*>(type, name.impl());
     }
 
-    bool deleteThisAndUpdateNodeRareDataIfAboutToRemoveLastList(Node*);
+    bool deleteThisAndUpdateNodeRareDataIfAboutToRemoveLastList(Node&);
 
     // Can be a ChildNodeList or an EmptyNodeList.
     NodeList* m_childNodeList;
     NodeListAtomicNameCacheMap m_atomicNameCaches;
     TagCollectionCacheNS m_tagCollectionCacheNS;
 };
 
 class NodeMutationObserverData {
     WTF_MAKE_NONCOPYABLE(NodeMutationObserverData); WTF_MAKE_FAST_ALLOCATED;
 public:
@@ skipping 46 matching lines @@
         , m_connectedFrameCount(0)
     { }
 
 private:
     unsigned m_connectedFrameCount : 10; // Must fit Page::maxNumberOfFrames.
 
     OwnPtr<NodeListsNodeData> m_nodeLists;
     OwnPtr<NodeMutationObserverData> m_mutationObserverData;
 };
 
-inline bool NodeListsNodeData::deleteThisAndUpdateNodeRareDataIfAboutToRemoveLastList(Node* ownerNode)
+inline bool NodeListsNodeData::deleteThisAndUpdateNodeRareDataIfAboutToRemoveLastList(Node& ownerNode)
 {
-    ASSERT(ownerNode);
-    ASSERT(ownerNode->nodeLists() == this);
+    ASSERT(ownerNode.nodeLists() == this);
     if ((m_childNodeList ? 1 : 0) + m_atomicNameCaches.size() + m_tagCollectionCacheNS.size() != 1)
         return false;
-    ownerNode->clearNodeLists();
+    ownerNode.clearNodeLists();
     return true;
 }
 
 // Ensure the 10 bits reserved for the m_connectedFrameCount cannot overflow
 COMPILE_ASSERT(Page::maxNumberOfFrames < 1024, Frame_limit_should_fit_in_rare_data_count);
 
 } // namespace WebCore
 
 #endif // NodeRareData_h