Add sync manager classes for backup/rollback:

sync/internal_api/sync_rollback_manager.h

Index: sync/internal_api/sync_rollback_manager.h
diff --git a/sync/internal_api/sync_rollback_manager.h b/sync/internal_api/sync_rollback_manager.h
new file mode 100644
index 0000000000000000000000000000000000000000..7c8e6947c6f51ca1636aaa0f70273695be1d50ba
--- /dev/null
+++ b/sync/internal_api/sync_rollback_manager.h
@@ -0,0 +1,60 @@
+// 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>
+
+#include "sync/internal_api/sync_rollback_manager_base.h"
+
+namespace syncer {
+
+// SyncRollbackManager restores user's data to pre-sync state using backup
+// DB created by SyncBackupManager.
+class SyncRollbackManager : public SyncRollbackManagerBase {
+ public:
+  SyncRollbackManager();
+  virtual ~SyncRollbackManager();
+
+  // SyncManager implementation.
+  virtual void Init(
+      const base::FilePath& database_location,
+      const WeakHandle<JsEventHandler>& event_handler,
+      const std::string& sync_server_and_path,
+      int sync_server_port,
+      bool use_ssl,
+      scoped_ptr<HttpPostProviderFactory> post_factory,
+      const std::vector<scoped_refptr<ModelSafeWorker> >& workers,
+      ExtensionsActivity* extensions_activity,
+      SyncManager::ChangeDelegate* change_delegate,
+      const SyncCredentials& credentials,
+      const std::string& invalidator_client_id,
+      const std::string& restored_key_for_bootstrapping,
+      const std::string& restored_keystore_key_for_bootstrapping,
+      InternalComponentsFactory* internal_components_factory,
+      Encryptor* encryptor,
+      scoped_ptr<UnrecoverableErrorHandler> unrecoverable_error_handler,
+      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);
+
+  std::map<ModelSafeGroup, scoped_refptr<ModelSafeWorker> > workers_;
+
+  SyncManager::ChangeDelegate* change_delegate_;
+
+  // Types that can be rolled back.
+  ModelTypeSet rollback_ready_types_;
+};
+
+}  // namespace syncer
+
+#endif  // SYNC_INTERNAL_API_SYNC_ROLLBACK_MANAGER_H_