Have Node::highestAncestor() return a reference

Source/core/inspector/PageConsoleAgent.cpp

 /*
  * Copyright (C) 2011 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 57 matching lines @@
 };
 
 void PageConsoleAgent::addInspectedNode(ErrorString* errorString, int nodeId)
 {
     Node* node = m_inspectorDOMAgent->nodeForId(nodeId);
     if (!node) {
         *errorString = "nodeId is not valid";
         return;
     }
     while (node->isInShadowTree()) {
-        Node* ancestor = node->highestAncestor();
-        if (!ancestor->isShadowRoot() || toShadowRoot(ancestor)->type() == ShadowRoot::AuthorShadowRoot)
+        Node& ancestor = node->highestAncestor();
+        if (!ancestor.isShadowRoot() || toShadowRoot(ancestor).type() == ShadowRoot::AuthorShadowRoot)
             break;
         // User agent shadow root, keep climbing up.
-        node = toShadowRoot(ancestor)->host();
+        node = toShadowRoot(ancestor).host();
     }
     m_injectedScriptManager->injectedScriptHost()->addInspectedObject(adoptPtr(new InspectableNode(node)));
 }
 
 } // namespace WebCore