Eliminate NOTIFICATION_HISTORY_LOADED notification

chrome/browser/prerender/prerender_local_predictor.h

Index: chrome/browser/prerender/prerender_local_predictor.h
diff --git a/chrome/browser/prerender/prerender_local_predictor.h b/chrome/browser/prerender/prerender_local_predictor.h
index 95ca574516c6a08e96ce2325a2c39669a20e6893..e0a5c340a7fa11f014bba73da5eea2cc9e341dde 100644
--- a/chrome/browser/prerender/prerender_local_predictor.h
+++ b/chrome/browser/prerender/prerender_local_predictor.h
@@ -11,6 +11,7 @@
 #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"
@@ -220,10 +221,6 @@ class PrerenderLocalPredictor : public history::HistoryServiceObserver,
   // 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_;
@@ -239,6 +236,9 @@ class PrerenderLocalPredictor : public history::HistoryServiceObserver,
 
   scoped_ptr<PrefetchList> prefetch_list_;
 
+  ScopedObserver<HistoryService, HistoryServiceObserver>
+      history_service_observer_;
+
   DISALLOW_COPY_AND_ASSIGN(PrerenderLocalPredictor);
 };