Remove content::NotificationObserver dependency from most Prefs code.

chrome/browser/media_gallery/media_file_system_registry.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.
 
 // MediaFileSystemRegistry implementation.
 
 #include "chrome/browser/media_gallery/media_file_system_registry.h"
 
 #include <set>
 #include <vector>
@@ skipping 17 matching lines @@
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/system_monitor/media_storage_util.h"
 #include "chrome/common/chrome_notification_types.h"
 #include "chrome/common/chrome_paths.h"
 #include "chrome/common/extensions/extension_constants.h"
 #include "chrome/common/extensions/extension_set.h"
 #include "chrome/common/extensions/extension.h"
 #include "chrome/common/pref_names.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/notification_details.h"
+#include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 #include "content/public/browser/notification_source.h"
 #include "content/public/browser/notification_types.h"
 #include "content/public/browser/render_process_host.h"
 #include "content/public/browser/render_view_host.h"
 #include "content/public/browser/web_contents.h"
 #include "webkit/fileapi/file_system_types.h"
 #include "webkit/fileapi/isolated_context.h"
 
 #if defined(SUPPORT_MTP_DEVICE_FILESYSTEM)
@@ skipping 623 matching lines @@
     system_monitor->AddDevicesChangedObserver(this);
 }
 
 MediaFileSystemRegistry::~MediaFileSystemRegistry() {
   // SystemMonitor may be NULL in unit tests.
   SystemMonitor* system_monitor = SystemMonitor::Get();
   if (system_monitor)
     system_monitor->RemoveDevicesChangedObserver(this);
 }
 
-void MediaFileSystemRegistry::Observe(
-    int type,
-    const content::NotificationSource& source,
-    const content::NotificationDetails& details) {
-  DCHECK_EQ(chrome::NOTIFICATION_PREF_CHANGED, type);
-  const std::string& pref_name =
-      *content::Details<std::string>(details).ptr();
+void MediaFileSystemRegistry::OnPreferenceChanged(
+    PrefServiceBase* prefs,
+    const std::string& pref_name) {
   DCHECK_EQ(std::string(prefs::kMediaGalleriesRememberedGalleries), pref_name);
 
   // Find the Profile that contains the source PrefService.
-  PrefService* prefs = content::Source<PrefService>(source).ptr();
   PrefChangeRegistrarMap::iterator pref_change_it =
       pref_change_registrar_map_.begin();
   for (; pref_change_it != pref_change_registrar_map_.end(); ++pref_change_it) {
     if (pref_change_it->first->GetPrefs() == prefs)
       break;
   }
   DCHECK(pref_change_it != pref_change_registrar_map_.end());
   Profile* profile = pref_change_it->first;
 
   // Get the Extensions, MediaGalleriesPreferences and ExtensionHostMap for
@@ skipping 60 matching lines @@
 
     PrefChangeRegistrarMap::iterator pref_it =
         pref_change_registrar_map_.find(profile);
     DCHECK(pref_it != pref_change_registrar_map_.end());
     delete pref_it->second;
     pref_change_registrar_map_.erase(pref_it);
   }
 }
 
 }  // namespace chrome