Introduce PrefRegistrySyncable, simplifying PrefServiceSyncable.

chrome/browser/profiles/chrome_version_service.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_PROFILES_CHROME_VERSION_SERVICE_H_
 #define CHROME_BROWSER_PROFILES_CHROME_VERSION_SERVICE_H_
 
 #include <string>
 
 #include "base/basictypes.h"
 
 class PrefService;
-class PrefServiceSyncable;
+class PrefRegistrySyncable;
 
 // This service manages a pref which is used to determine the version of
 // Chrome by which the profile was created.
 class ChromeVersionService {
  public:
   // Register the user pref we use.
-  static void RegisterUserPrefs(PrefServiceSyncable* prefs);
+  static void RegisterUserPrefs(PrefRegistrySyncable* registry);
 
   // Sets the version string in the pref for the current profile.
   static void SetVersion(PrefService* prefs, const std::string& version);
 
   // Returns the version of Chrome which created the profile.
   static std::string GetVersion(PrefService* prefs);
 
   // Handles setting the profile.created_by_version Pref
   static void OnProfileLoaded(PrefService* prefs, bool is_new_profile);
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(ChromeVersionService);
 };
 
 #endif  // CHROME_BROWSER_PROFILES_CHROME_VERSION_SERVICE_H_