Introduce //components/user_prefs, use to eliminate c/b/prefs dependency in Autofill.

chrome/browser/media_galleries/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_galleries/media_galleries_preferences_factory.h"
 
 #include "chrome/browser/media_galleries/media_galleries_preferences.h"
-#include "chrome/browser/prefs/pref_registry_syncable.h"
 #include "chrome/browser/profiles/profile_dependency_manager.h"
+#include "components/user_prefs/pref_registry_syncable.h"
 
 // static
 chrome::MediaGalleriesPreferences*
 MediaGalleriesPreferencesFactory::GetForProfile(Profile* profile) {
   return static_cast<chrome::MediaGalleriesPreferences*>(
       GetInstance()->GetServiceForProfile(profile, true));
 }
 
 // static
 MediaGalleriesPreferencesFactory*
@@ skipping 13 matching lines @@
 }
 
 void MediaGalleriesPreferencesFactory::RegisterUserPrefs(
     PrefRegistrySyncable* prefs) {
   chrome::MediaGalleriesPreferences::RegisterUserPrefs(prefs);
 }
 
 bool MediaGalleriesPreferencesFactory::ServiceRedirectedInIncognito() const {
   return true;
 }