Get rid of unnecessary isChildNodeList() virtual call in clearChildNodeListCache()

Source/core/dom/NodeListsNodeData.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 19 matching lines @@
 #include "platform/heap/Handle.h"
 #include "wtf/text/AtomicString.h"
 #include "wtf/text/StringHash.h"
 
 namespace blink {
 
 class NodeListsNodeData FINAL : public NoBaseWillBeGarbageCollectedFinalized<NodeListsNodeData> {
     WTF_MAKE_NONCOPYABLE(NodeListsNodeData);
     WTF_MAKE_FAST_ALLOCATED_WILL_BE_REMOVED;
 public:
-    void clearChildNodeListCache()
+    ChildNodeList* childNodeList(ContainerNode& node)
     {
-        if (m_childNodeList && m_childNodeList->isChildNodeList())
-            toChildNodeList(m_childNodeList)->invalidateCache();
+        ASSERT_UNUSED(node, !m_childNodeList || node == m_childNodeList->virtualOwnerNode());
+        return toChildNodeList(m_childNodeList);
     }
 
     PassRefPtrWillBeRawPtr<ChildNodeList> ensureChildNodeList(ContainerNode& node)
     {
         if (m_childNodeList)
             return toChildNodeList(m_childNodeList);
         RefPtrWillBeRawPtr<ChildNodeList> list = ChildNodeList::create(node);
         m_childNodeList = list.get();
         return list.release();
     }
@@ skipping 178 matching lines @@
     if ((m_childNodeList ? 1 : 0) + m_atomicNameCaches.size() + m_tagCollectionCacheNS.size() != 1)
         return false;
     ownerNode.clearNodeLists();
     return true;
 }
 #endif
 
 } // namespace blink
 
 #endif // NodeListsNodeData_h