Introduce PrefRegistrySyncable, simplifying PrefServiceSyncable.

chrome/browser/media_gallery/media_galleries_preferences_factory.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.
 
 #include "chrome/browser/media_gallery/media_galleries_preferences_factory.h"
 
 #include "chrome/browser/media_gallery/media_galleries_preferences.h"
+#include "chrome/browser/prefs/pref_registry_syncable.h"
 #include "chrome/browser/profiles/profile_dependency_manager.h"
 
 // static
 chrome::MediaGalleriesPreferences*
 MediaGalleriesPreferencesFactory::GetForProfile(Profile* profile) {
   return static_cast<chrome::MediaGalleriesPreferences*>(
       GetInstance()->GetServiceForProfile(profile, true));
 }
 
 // static
 MediaGalleriesPreferencesFactory*
 MediaGalleriesPreferencesFactory::GetInstance() {
   return Singleton<MediaGalleriesPreferencesFactory>::get();
 }
 
 MediaGalleriesPreferencesFactory::MediaGalleriesPreferencesFactory()
     : ProfileKeyedServiceFactory("MediaGalleriesPreferences",
                                  ProfileDependencyManager::GetInstance()) {}
 
 MediaGalleriesPreferencesFactory::~MediaGalleriesPreferencesFactory() {}
 
 ProfileKeyedService* MediaGalleriesPreferencesFactory::BuildServiceInstanceFor(
     Profile* profile) const {
   return new chrome::MediaGalleriesPreferences(profile);
 }
 
 void MediaGalleriesPreferencesFactory::RegisterUserPrefs(
-    PrefServiceSyncable* prefs) {
-    chrome::MediaGalleriesPreferences::RegisterUserPrefs(prefs);
+    PrefRegistrySyncable* prefs) {
+  chrome::MediaGalleriesPreferences::RegisterUserPrefs(prefs);
 }
 
 bool MediaGalleriesPreferencesFactory::ServiceRedirectedInIncognito() const {
   return true;
 }