Add a ClientAction used by SyncRollbackManager to notify PSS that rollback is

sync/internal_api/sync_rollback_manager.h

 // Copyright 2014 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 SYNC_INTERNAL_API_SYNC_ROLLBACK_MANAGER_H_
 #define SYNC_INTERNAL_API_SYNC_ROLLBACK_MANAGER_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 29 matching lines @@
       ReportUnrecoverableErrorFunction
           report_unrecoverable_error_function,
       CancelationSignal* cancelation_signal) OVERRIDE;
   virtual void StartSyncingNormally(
       const ModelSafeRoutingInfo& routing_info) OVERRIDE;
 
  private:
   // Deletes specified entries in local model.
   SyncerError DeleteOnWorkerThread(ModelType type, std::vector<int64> handles);
 
+  void NotifyRollbackDone();
+
   std::map<ModelSafeGroup, scoped_refptr<ModelSafeWorker> > workers_;
 
   SyncManager::ChangeDelegate* change_delegate_;
 
   // Types that can be rolled back.
   ModelTypeSet rollback_ready_types_;
 
   DISALLOW_COPY_AND_ASSIGN(SyncRollbackManager);
 };
 
 }  // namespace syncer
 
 #endif  // SYNC_INTERNAL_API_SYNC_ROLLBACK_MANAGER_H_