Add sync manager classes for backup/rollback:

sync/internal_api/sync_rollback_manager_base.h

Index: sync/internal_api/sync_rollback_manager_base.h
diff --git a/sync/internal_api/sync_rollback_manager_base.h b/sync/internal_api/sync_rollback_manager_base.h
new file mode 100644
index 0000000000000000000000000000000000000000..646d3bd3b66bd01c269ae7124e3c87d80c60c915
--- /dev/null
+++ b/sync/internal_api/sync_rollback_manager_base.h
@@ -0,0 +1,143 @@
+// 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_BASE_H_
+#define SYNC_INTERNAL_API_SYNC_ROLLBACK_MANAGER_BASE_H_
+
+#include <string>
+#include <vector>
+
+#include "sync/internal_api/public/http_post_provider_factory.h"
+#include "sync/internal_api/public/sync_manager.h"
+#include "sync/internal_api/public/user_share.h"
+#include "sync/js/js_backend.h"
+#include "sync/syncable/directory_change_delegate.h"
+#include "sync/syncable/transaction_observer.h"
+
+namespace syncer {
+
+class WriteTransaction;
+
+// Base class of sync managers used for backup and rollback. Initialize sync
+// DB for backup types as needed. Most of functions are no ops.

[Nicolas Zea, 2014/04/14 21:36:31]

I think this would be a good place to go into more detail. How does this behave
differently? Which functions aren't no-ops and why?

[haitaol1, 2014/04/15 00:19:06]

Done.

+class SyncRollbackManagerBase :
+    public SyncManager,
+    public JsBackend,

[Nicolas Zea, 2014/04/14 21:36:31]

Why do we need the JsBackend?

[haitaol1, 2014/04/15 00:19:06]

This was used to query directory stats, but it may have changed. Removed.

+    public syncable::DirectoryChangeDelegate,
+    public syncable::TransactionObserver {

[Nicolas Zea, 2014/04/14 21:36:31]

transaction observer doesn't seem necessary either

[haitaol1, 2014/04/15 00:19:06]

There's a DCHECK(transaction_observer.IsInitialized()) in constructor of
Directory::Kernel

+ public:
+  SyncRollbackManagerBase();
+  virtual ~SyncRollbackManagerBase();
+
+  // 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 ThrowUnrecoverableError() OVERRIDE;
+  virtual ModelTypeSet InitialSyncEndedTypes() OVERRIDE;
+  virtual ModelTypeSet GetTypesWithEmptyProgressMarkerToken(
+      ModelTypeSet types) OVERRIDE;
+  virtual bool PurgePartiallySyncedTypes() OVERRIDE;
+  virtual void UpdateCredentials(const SyncCredentials& credentials) OVERRIDE;
+  virtual void StartSyncingNormally(const ModelSafeRoutingInfo& routing_info)
+      OVERRIDE;
+  virtual void ConfigureSyncer(
+      ConfigureReason reason,
+      ModelTypeSet to_download,
+      ModelTypeSet to_purge,
+      ModelTypeSet to_journal,
+      ModelTypeSet to_unapply,
+      const ModelSafeRoutingInfo& new_routing_info,
+      const base::Closure& ready_task,
+      const base::Closure& retry_task) OVERRIDE;
+  virtual void OnInvalidatorStateChange(InvalidatorState state) OVERRIDE;
+  virtual void OnIncomingInvalidation(
+      const ObjectIdInvalidationMap& invalidation_map) OVERRIDE;
+  virtual void AddObserver(SyncManager::Observer* observer) OVERRIDE;
+  virtual void RemoveObserver(SyncManager::Observer* observer) OVERRIDE;
+  virtual SyncStatus GetDetailedStatus() const OVERRIDE;
+  virtual void SaveChanges() OVERRIDE;
+  virtual void ShutdownOnSyncThread() OVERRIDE;
+  virtual UserShare* GetUserShare() OVERRIDE;
+  virtual const std::string cache_guid() OVERRIDE;
+  virtual bool ReceivedExperiment(Experiments* experiments) OVERRIDE;
+  virtual bool HasUnsyncedItems() OVERRIDE;
+  virtual SyncEncryptionHandler* GetEncryptionHandler() OVERRIDE;
+  virtual void RefreshTypes(ModelTypeSet types) OVERRIDE;
+  virtual std::string GetOwnerName() const OVERRIDE;
+  virtual base::WeakPtr<syncer::SyncCore> GetSyncCore() OVERRIDE;
+  virtual ScopedVector<syncer::ProtocolEvent> GetBufferedProtocolEvents()
+      OVERRIDE;
+  virtual scoped_ptr<base::ListValue> GetAllNodesForType(
+      syncer::ModelType type) OVERRIDE;
+
+  // JsBackend implementation.
+  virtual void SetJsEventHandler(
+      const WeakHandle<JsEventHandler>& event_handler) OVERRIDE;
+  virtual void ProcessJsMessage(
+      const std::string& name, const JsArgList& args,
+      const WeakHandle<JsReplyHandler>& reply_handler) OVERRIDE;
+
+  // DirectoryChangeDelegate implementation.
+  virtual void HandleTransactionCompleteChangeEvent(
+      ModelTypeSet models_with_changes) OVERRIDE;
+  virtual ModelTypeSet HandleTransactionEndingChangeEvent(
+      const syncable::ImmutableWriteTransactionInfo& write_transaction_info,
+      syncable::BaseTransaction* trans) OVERRIDE;
+  virtual void HandleCalculateChangesChangeEventFromSyncApi(
+      const syncable::ImmutableWriteTransactionInfo& write_transaction_info,
+      syncable::BaseTransaction* trans,
+      std::vector<int64>* entries_changed) OVERRIDE;
+  virtual void HandleCalculateChangesChangeEventFromSyncer(
+      const syncable::ImmutableWriteTransactionInfo& write_transaction_info,
+      syncable::BaseTransaction* trans,
+      std::vector<int64>* entries_changed) OVERRIDE;
+
+  // syncable::TransactionObserver implementation.
+  virtual void OnTransactionWrite(
+      const syncable::ImmutableWriteTransactionInfo& write_transaction_info,
+      ModelTypeSet models_with_changes) OVERRIDE;
+
+ protected:
+  UserShare share_;
+  SyncStatus status_;
+  ObserverList<SyncManager::Observer> observers_;
+
+ private:
+  void NotifyInitializationSuccess();
+  void NotifyInitializationFailure();
+
+  bool InitBackupDB(
+      const base::FilePath& sync_folder,
+      InternalComponentsFactory* internal_components_factory);
+
+  bool InitTypeRootNode(ModelType type);
+  void InitBookmarkFolder(const std::string& folder);
+
+  scoped_ptr<UnrecoverableErrorHandler> unrecoverable_error_handler_;
+  ReportUnrecoverableErrorFunction report_unrecoverable_error_function_;
+
+  base::WeakPtrFactory<SyncRollbackManagerBase> weak_ptr_factory_;
+};
+
+}  // namespace syncer
+
+#endif  // SYNC_INTERNAL_API_SYNC_ROLLBACK_MANAGER_BASE_H_