[SyncFS] Add completion callback to PromoteDemotedChanges (1/3)

chrome/browser/sync_file_system/remote_file_sync_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_SYNC_FILE_SYSTEM_REMOTE_FILE_SYNC_SERVICE_H_
 #define CHROME_BROWSER_SYNC_FILE_SYSTEM_REMOTE_FILE_SYNC_SERVICE_H_
 
 #include <map>
 #include <set>
 #include <string>
@@ skipping 193 matching lines @@
   virtual void DumpDatabase(const ListCallback& callback) = 0;
 
   // Enables or disables the background sync.
   // Setting this to false should disable the synchronization (and make
   // the service state to REMOTE_SERVICE_DISABLED), while setting this to
   // true does not necessarily mean the service is actually turned on
   // (for example if Chrome is offline the service state will become
   // REMOTE_SERVICE_TEMPORARY_UNAVAILABLE).
   virtual void SetSyncEnabled(bool enabled) = 0;
 
-  virtual void PromoteDemotedChanges() = 0;
+  virtual void PromoteDemotedChanges(const base::Closure& callback) = 0;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(RemoteFileSyncService);
 };
 
 }  // namespace sync_file_system
 
 #endif  // CHROME_BROWSER_SYNC_FILE_SYSTEM_REMOTE_FILE_SYNC_SERVICE_H_