Have Frame::tree() return a reference

Source/web/StorageAreaProxy.cpp

 /*
  * Copyright (C) 2009 Google Inc. All Rights Reserved.
  *           (C) 2008 Apple Inc.
  *
  * 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 136 matching lines @@
 {
     return m_storageArea->memoryBytesUsedByCache();
 }
 
 void StorageAreaProxy::dispatchLocalStorageEvent(const String& key, const String& oldValue, const String& newValue,
                                                  SecurityOrigin* securityOrigin, const KURL& pageURL, WebKit::WebStorageArea* sourceAreaInstance, bool originatedInProcess)
 {
     // FIXME: This looks suspicious. Why doesn't this use allPages instead?
     const HashSet<Page*>& pages = PageGroup::sharedGroup()->pages();
     for (HashSet<Page*>::const_iterator it = pages.begin(); it != pages.end(); ++it) {
-        for (Frame* frame = (*it)->mainFrame(); frame; frame = frame->tree()->traverseNext()) {
+        for (Frame* frame = (*it)->mainFrame(); frame; frame = frame->tree().traverseNext()) {
             Storage* storage = frame->domWindow()->optionalLocalStorage();
             if (storage && frame->document()->securityOrigin()->equal(securityOrigin) && !isEventSource(storage, sourceAreaInstance))
                 frame->document()->enqueueWindowEvent(StorageEvent::create(EventTypeNames::storage, key, oldValue, newValue, pageURL, storage));
         }
         InspectorInstrumentation::didDispatchDOMStorageEvent(*it, key, oldValue, newValue, LocalStorage, securityOrigin);
     }
 }
 
 static Page* findPageWithSessionStorageNamespace(const WebKit::WebStorageNamespace& sessionNamespace)
 {
     // FIXME: This looks suspicious. Why doesn't this use allPages instead?
     const HashSet<Page*>& pages = PageGroup::sharedGroup()->pages();
     for (HashSet<Page*>::const_iterator it = pages.begin(); it != pages.end(); ++it) {
         const bool dontCreateIfMissing = false;
         StorageNamespaceProxy* proxy = static_cast<StorageNamespaceProxy*>((*it)->sessionStorage(dontCreateIfMissing));
         if (proxy && proxy->isSameNamespace(sessionNamespace))
             return *it;
     }
     return 0;
 }
 
 void StorageAreaProxy::dispatchSessionStorageEvent(const String& key, const String& oldValue, const String& newValue,
                                                    SecurityOrigin* securityOrigin, const KURL& pageURL, const WebKit::WebStorageNamespace& sessionNamespace,
                                                    WebKit::WebStorageArea* sourceAreaInstance, bool originatedInProcess)
 {
     Page* page = findPageWithSessionStorageNamespace(sessionNamespace);
     if (!page)
         return;
 
-    for (Frame* frame = page->mainFrame(); frame; frame = frame->tree()->traverseNext()) {
+    for (Frame* frame = page->mainFrame(); frame; frame = frame->tree().traverseNext()) {
         Storage* storage = frame->domWindow()->optionalSessionStorage();
         if (storage && frame->document()->securityOrigin()->equal(securityOrigin) && !isEventSource(storage, sourceAreaInstance))
             frame->document()->enqueueWindowEvent(StorageEvent::create(EventTypeNames::storage, key, oldValue, newValue, pageURL, storage));
     }
     InspectorInstrumentation::didDispatchDOMStorageEvent(page, key, oldValue, newValue, SessionStorage, securityOrigin);
 }
 
 bool StorageAreaProxy::isEventSource(Storage* storage, WebKit::WebStorageArea* sourceAreaInstance)
 {
     ASSERT(storage);
     StorageAreaProxy* areaProxy = static_cast<StorageAreaProxy*>(storage->area());
     return areaProxy->m_storageArea == sourceAreaInstance;
 }
 
 } // namespace WebCore