Refactor HistoryService to not send NOTIFICATION_FAVICON_CHANGED

chrome/browser/history/history_backend.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_HISTORY_HISTORY_BACKEND_H_
 #define CHROME_BROWSER_HISTORY_HISTORY_BACKEND_H_
 
 #include <set>
 #include <string>
 #include <utility>
@@ skipping 101 matching lines @@
     // Sets the in-memory history backend. The in-memory backend is created by
     // the main backend. For non-unit tests, this happens on the background
     // thread. It is to be used on the main thread, so this would transfer
     // it to the history service. Unit tests can override this behavior.
     //
     // This function is NOT guaranteed to be called. If there is an error,
     // there may be no in-memory database.
     virtual void SetInMemoryBackend(
         scoped_ptr<InMemoryHistoryBackend> backend) = 0;
 
+    // Notify HistoryService that some URLs favicon changed that will forward
+    // the events to the FaviconChangedObservers in the correct thread.
+    virtual void NotifyFaviconChanged(const std::set<GURL>& urls) = 0;
+
     // Broadcasts the specified notification to the notification service.
     // This is implemented here because notifications must only be sent from
     // the main thread. This is the only method that doesn't identify the
     // caller because notifications must always be sent.
     virtual void BroadcastNotifications(int type,
                                         scoped_ptr<HistoryDetails> details) = 0;
 
     // Invoked when the backend has finished loading the db.
     virtual void DBLoaded() = 0;
 
@@ skipping 769 matching lines @@
 
   // Listens for the system being under memory pressure.
   scoped_ptr<base::MemoryPressureListener> memory_pressure_listener_;
 
   DISALLOW_COPY_AND_ASSIGN(HistoryBackend);
 };
 
 }  // namespace history
 
 #endif  // CHROME_BROWSER_HISTORY_HISTORY_BACKEND_H_