[Sync] Add a sanity integration test for USS.

components/browser_sync/browser/profile_sync_components_factory_impl.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 COMPONENTS_BROWSER_SYNC_BROWSER_PROFILE_SYNC_COMPONENTS_FACTORY_IMPL_H__
 #define COMPONENTS_BROWSER_SYNC_BROWSER_PROFILE_SYNC_COMPONENTS_FACTORY_IMPL_H__
 
 #include <memory>
 #include <string>
 
@@ skipping 70 matching lines @@
       std::unique_ptr<syncer::AttachmentStoreForSync> attachment_store,
       const syncer::UserShare& user_share,
       const std::string& store_birthday,
       syncer::ModelType model_type,
       syncer::AttachmentService::Delegate* delegate) override;
   sync_driver::SyncApiComponentFactory::SyncComponents
   CreateBookmarkSyncComponents(
       sync_driver::SyncService* sync_service,
       std::unique_ptr<syncer::DataTypeErrorHandler> error_handler) override;
 
+  // Sets a bit that determines whether PREFERENCES should be registered with a
+  // ModelTypeController for testing purposes.
+  static void OverridePrefsForUssTest(bool use_uss);
+
  private:
   // Register data types which are enabled on both desktop and mobile.
   // |disabled_types| and |enabled_types| correspond only to those types
   // being explicitly enabled/disabled by the command line.
   void RegisterCommonDataTypes(sync_driver::SyncService* sync_service,
                                syncer::ModelTypeSet disabled_types,
                                syncer::ModelTypeSet enabled_types);
 
   void DisableBrokenType(syncer::ModelType type,
                          const tracked_objects::Location& from_here,
                          const std::string& message);
 
   // Client/platform specific members.
   sync_driver::SyncClient* const sync_client_;
   const version_info::Channel channel_;
   const std::string version_;
   const bool is_tablet_;
   const base::CommandLine command_line_;
   const char* history_disabled_pref_;
   const GURL sync_service_url_;
   const scoped_refptr<base::SingleThreadTaskRunner> ui_thread_;
   const scoped_refptr<base::SingleThreadTaskRunner> db_thread_;
   OAuth2TokenService* const token_service_;
   net::URLRequestContextGetter* const url_request_context_getter_;
   const scoped_refptr<autofill::AutofillWebDataService> web_data_service_;
   const scoped_refptr<password_manager::PasswordStore> password_store_;
 
   base::WeakPtrFactory<ProfileSyncComponentsFactoryImpl> weak_factory_;
 
+  // Whether to override PREFERENCES to use USS.
+  static bool override_prefs_controller_to_uss_for_test_;
+
   DISALLOW_COPY_AND_ASSIGN(ProfileSyncComponentsFactoryImpl);
 };
 
 #endif  // COMPONENTS_BROWSER_SYNC_BROWSER_PROFILE_SYNC_COMPONENTS_FACTORY_IMPL_H__