Eliminate NOTIFICATION_HISTORY_LOADED notification

chrome/browser/prerender/prerender_local_predictor.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_PRERENDER_PRERENDER_LOCAL_PREDICTOR_H_
 #define CHROME_BROWSER_PRERENDER_PRERENDER_LOCAL_PREDICTOR_H_
 
 #include <map>
 #include <vector>
 
 #include "base/containers/hash_tables.h"
 #include "base/memory/scoped_vector.h"
 #include "base/memory/weak_ptr.h"
+#include "base/scoped_observer.h"
 #include "base/task/cancelable_task_tracker.h"
 #include "base/timer/timer.h"
 #include "chrome/browser/history/visit_database.h"
 #include "components/history/core/browser/history_service_observer.h"
 #include "content/public/browser/session_storage_namespace.h"
 #include "net/url_request/url_fetcher_delegate.h"
 #include "url/gurl.h"
 
 class HistoryService;
 
@@ skipping 189 matching lines @@
   typedef std::map<net::URLFetcher*, CandidatePrerenderInfo*>
       OutstandingFetchers;
   OutstandingFetchers outstanding_prerender_service_requests_;
   PrerenderManager* prerender_manager_;
   base::OneShotTimer<PrerenderLocalPredictor> timer_;
 
   // Delay after which to initialize, to avoid putting to much load on the
   // database thread early on when Chrome is starting up.
   static const int kInitDelayMs = 5 * 1000;
 
-  // Whether we're registered with the history service as a
-  // history::HistoryServiceObserver.
-  bool is_history_service_observer_;
-
   base::CancelableTaskTracker history_db_tracker_;
 
   scoped_ptr<std::vector<history::BriefVisitInfo> > visit_history_;
 
   scoped_ptr<PrerenderProperties> current_prerender_;
   scoped_ptr<PrerenderProperties> last_swapped_in_prerender_;
 
   ScopedVector<PrerenderProperties> issued_prerenders_;
 
   base::hash_set<int64> url_whitelist_;
 
   base::WeakPtrFactory<PrerenderLocalPredictor> weak_factory_;
 
   scoped_ptr<PrefetchList> prefetch_list_;
 
+  ScopedObserver<HistoryService, HistoryServiceObserver>
+      history_service_observer_;
+
   DISALLOW_COPY_AND_ASSIGN(PrerenderLocalPredictor);
 };
 
 }  // namespace prerender
 
 #endif  // CHROME_BROWSER_PRERENDER_PRERENDER_LOCAL_PREDICTOR_H_