Refactor HistoryService to not send NOTIFICATION_FAVICON_CHANGED

chrome/browser/history/history_service.cc

 // 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.
 
 // The history system runs on a background thread so that potentially slow
 // database operations don't delay the browser. This backend processing is
 // represented by HistoryBackend. The HistoryService's job is to dispatch to
 // that thread.
 //
 // Main thread                       History thread
@@ skipping 140 matching lines @@
 
   virtual void SetInMemoryBackend(
       scoped_ptr<history::InMemoryHistoryBackend> backend) OVERRIDE {
     // Send the backend to the history service on the main thread.
     service_task_runner_->PostTask(
         FROM_HERE,
         base::Bind(&HistoryService::SetInMemoryBackend, history_service_,
                    base::Passed(&backend)));
   }
 
+  virtual void NotifyFaviconChanged(const std::set<GURL>& urls) OVERRIDE {
+    // Send the notification to the history service on the main thread.
+    service_task_runner_->PostTask(
+        FROM_HERE,
+        base::Bind(
+            &HistoryService::NotifyFaviconChanged, history_service_, urls));
+  }
+
   virtual void BroadcastNotifications(
       int type,
       scoped_ptr<history::HistoryDetails> details) OVERRIDE {
     // Send the notification on the history thread.
     if (content::NotificationService::current()) {
       content::Details<history::HistoryDetails> det(details.get());
       content::NotificationService::current()->Notify(
           type, content::Source<Profile>(profile_), det);
     }
     // Send the notification to the history service on the main thread.
@@ skipping 1053 matching lines @@
   DCHECK(thread_checker_.CalledOnValidThread());
   visit_database_observers_.RemoveObserver(observer);
 }
 
 void HistoryService::NotifyVisitDBObserversOnAddVisit(
     const history::BriefVisitInfo& info) {
   DCHECK(thread_checker_.CalledOnValidThread());
   FOR_EACH_OBSERVER(history::VisitDatabaseObserver, visit_database_observers_,
                     OnAddVisit(info));
 }
+
+scoped_ptr<base::CallbackList<void(const std::set<GURL>&)>::Subscription>
+HistoryService::AddFaviconChangedCallback(
+    const HistoryService::OnFaviconChangedCallback& callback) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  return favicon_changed_callback_list_.Add(callback);
+}
+
+void HistoryService::NotifyFaviconChanged(
+    const std::set<GURL>& changed_favicons) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  favicon_changed_callback_list_.Notify(changed_favicons);
+}