Add sync manager classes for backup/rollback:

sync/internal_api/sync_backup_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_BACKUP_MANAGER_H_
+#define SYNC_INTERNAL_API_SYNC_BACKUP_MANAGER_H_
+
+#include <set>
+
+#include "sync/internal_api/sync_rollback_manager_base.h"
+
+namespace syncer {
+
+// SyncBackupManager runs before user signs in to sync to back up user's data
+// before sync starts. The data that's backed up can be used to restore user's
+// settings to pre-sync state.
+class SyncBackupManager : public SyncRollbackManagerBase {

[Nicolas Zea, 2014/04/17 18:22:56]

do these new classes need SYNC_EXPORT?

[haitaol1, 2014/04/17 19:30:38]

They are not used by chrome/browser/sync. Looks like SYNC_EXPORT_PRIVATE should
be used according to:
https://sites.google.com/a/google.com/chromesync/sync-client/sync-and-compone...

On 2014/04/17 18:22:56, Nicolas Zea wrote:

+ public:
+  SyncBackupManager();
+  virtual ~SyncBackupManager();
+
+  // SyncManager implementation.
+  virtual void SaveChanges() OVERRIDE;
+
+  // DirectoryChangeDelegate implementation.
+  virtual ModelTypeSet HandleTransactionEndingChangeEvent(
+      const syncable::ImmutableWriteTransactionInfo& write_transaction_info,
+      syncable::BaseTransaction* trans) OVERRIDE;
+
+ private:
+  // Replaces local IDs with server IDs and clear unsynced bit of modified
+  // entries.
+  void NormalizeEntries();
+
+  // Handles of unsynced entries caused by local model changes.
+  std::set<int64> unsynced_;
+
+  // True if NormalizeEntries() is being called.
+  bool in_normalization_;

[Nicolas Zea, 2014/04/17 18:22:56]

DISALLOW_COPY_AND_ASSIGN (here and in the other classes)

[haitaol1, 2014/04/17 19:30:38]

Done.

+};
+
+}  // namespace syncer
+
+#endif  // SYNC_INTERNAL_API_SYNC_BACKUP_MANAGER_H_