Have Frame::tree() return a reference

Source/core/inspector/InspectorApplicationCacheAgent.cpp

 /*
  * Copyright (C) 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2010 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:
  * 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 84 matching lines @@
 void InspectorApplicationCacheAgent::networkStateChanged(bool online)
 {
     m_frontend->networkStateUpdated(online);
 }
 
 void InspectorApplicationCacheAgent::getFramesWithManifests(ErrorString*, RefPtr<TypeBuilder::Array<TypeBuilder::ApplicationCache::FrameWithManifest> >& result)
 {
     result = TypeBuilder::Array<TypeBuilder::ApplicationCache::FrameWithManifest>::create();
 
     Frame* mainFrame = m_pageAgent->mainFrame();
-    for (Frame* frame = mainFrame; frame; frame = frame->tree()->traverseNext(mainFrame)) {
+    for (Frame* frame = mainFrame; frame; frame = frame->tree().traverseNext(mainFrame)) {
         DocumentLoader* documentLoader = frame->loader()->documentLoader();
         if (!documentLoader)
             continue;
 
         ApplicationCacheHost* host = documentLoader->applicationCacheHost();
         ApplicationCacheHost::CacheInfo info = host->applicationCacheInfo();
         String manifestURL = info.m_manifest.string();
         if (!manifestURL.isEmpty()) {
             RefPtr<TypeBuilder::ApplicationCache::FrameWithManifest> value = TypeBuilder::ApplicationCache::FrameWithManifest::create()
                 .setFrameId(m_pageAgent->frameId(frame))
@@ skipping 81 matching lines @@
 
     RefPtr<TypeBuilder::ApplicationCache::ApplicationCacheResource> value = TypeBuilder::ApplicationCache::ApplicationCacheResource::create()
         .setUrl(resourceInfo.m_resource.string())
         .setSize(static_cast<int>(resourceInfo.m_size))
         .setType(builder.toString());
     return value;
 }
 
 } // namespace WebCore