[Sync] Adds a new switch for enabling the new local server backend.

components/sync/engine/sync_manager.h

 // Copyright 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_SYNC_ENGINE_SYNC_MANAGER_H_
 #define COMPONENTS_SYNC_ENGINE_SYNC_MANAGER_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 206 matching lines @@
     // Path in which to create or open sync's sqlite database (aka the
     // directory).
     base::FilePath database_location;
 
     // Used to propagate events to chrome://sync-internals.  Optional.
     WeakHandle<JsEventHandler> event_handler;
 
     // URL of the sync server.
     GURL service_url;
 
+    // Whether the local backend provided by the LoopbackServer should be used
+    // and the location of the local sync backend storage.
+    bool enable_local_sync_backend;
+    base::FilePath local_sync_backend_folder;
+
     // Used to communicate with the sync server.
     std::unique_ptr<HttpPostProviderFactory> post_factory;
 
     std::vector<scoped_refptr<ModelSafeWorker>> workers;
 
     // Must outlive SyncManager.
     ExtensionsActivity* extensions_activity;
 
     // Must outlive SyncManager.
     ChangeDelegate* change_delegate;
@@ skipping 156 matching lines @@
 
   // Updates Sync's tracking of whether the cookie jar has a mismatch with the
   // chrome account. See ClientConfigParams proto message for more info.
   // Note: this does not trigger a sync cycle. It just updates the sync context.
   virtual void OnCookieJarChanged(bool account_mismatch, bool empty_jar) = 0;
 };
 
 }  // namespace syncer
 
 #endif  // COMPONENTS_SYNC_ENGINE_SYNC_MANAGER_H_