[sync] Add backup time in synced device info so that server can flag device

sync/internal_api/public/util/sync_db_util.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_PUBLIC_UTIL_SYNC_DB_UTIL_H_
+#define SYNC_INTERNAL_API_PUBLIC_UTIL_SYNC_DB_UTIL_H_
+
+#include "base/callback.h"
+#include "base/memory/ref_counted.h"
+#include "base/time/time.h"
+
+namespace base {
+class FilePath;
+class SingleThreadTaskRunner;
+}  // namespace base
+
+namespace syncer {
+
+// Check integrity of sync DB under |sync_dir|. Invoke |callback| with last
+// modified time if integrity check passes, with NULL time otherwise.

[Nicolas Zea, 2014/06/13 22:36:41]

Mention what thread this should be run on?

[haitaol1, 2014/06/13 23:28:25]

Done.

+void CheckSyncDbLastModifiedTime(
+    const base::FilePath& sync_dir,
+    scoped_refptr<base::SingleThreadTaskRunner> callback_runner,
+    base::Callback<void(base::Time)> callback);
+
+}  // namesapce syncer
+
+#endif  // SYNC_INTERNAL_API_PUBLIC_UTIL_SYNC_DB_UTIL_H_