mash: switch to the new pref service

services/preferences/public/cpp/pref_service_factory.h

 // Copyright 2017 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.
 
 // This provides a way for any service to connect to the pref service to access
 // the application's current preferences.
 
 // Access is provided through a synchronous interface, exposed using the
 // |PrefService| class.
 
 #ifndef SERVICES_PREFERENCES_PUBLIC_CPP_PREF_SERVICE_FACTORY_H_
 #define SERVICES_PREFERENCES_PUBLIC_CPP_PREF_SERVICE_FACTORY_H_
 
 #include <memory>
 
 #include "base/callback.h"
+#include "services/preferences/public/interfaces/preferences.mojom.h"
 
 class PrefRegistry;
 class PrefService;
 
 namespace service_manager {
 class Connector;
 }
 
 namespace prefs {
 
 // Note that |PrefService| might not be fully initialized yet and thus you need
 // to call |AddPrefInitObserver| on it before using it. Passed |nullptr| on
 // failure.
 using ConnectCallback = base::Callback<void(std::unique_ptr<::PrefService>)>;
 
 // Create a |PrefService| object acting as a client library for the pref
 // service, by connecting to the service using |connector|. Connecting is
 // asynchronous and |callback| will be called when it has been established. All
 // preferences that will be accessed need to be registered in |pref_registry|
 // first.
-void ConnectToPrefService(service_manager::Connector* connector,
-                          scoped_refptr<PrefRegistry> pref_registry,
-                          ConnectCallback callback);
+void ConnectToPrefService(
+    service_manager::Connector* connector,
+    scoped_refptr<PrefRegistry> pref_registry,
+    ConnectCallback callback,
+    base::StringPiece service_name = mojom::kPrefStoreServiceName);
 
 }  // namespace prefs
 
 #endif  // SERVICES_PREFERENCES_PUBLIC_CPP_PREF_SERVICE_FACTORY_H_