[Sync] Fix bug where DeviceInfo is missing a backup timestamp

chrome/browser/sync/profile_sync_service.h

 // Copyright (c) 2012 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 CHROME_BROWSER_SYNC_PROFILE_SYNC_SERVICE_H_
 #define CHROME_BROWSER_SYNC_PROFILE_SYNC_SERVICE_H_
 
 #include <set>
 #include <string>
 #include <utility>
@@ skipping 977 matching lines @@
   Profile* profile_;
 
   // The class that handles getting, setting, and persisting sync
   // preferences.
   sync_driver::SyncPrefs sync_prefs_;
 
   // TODO(ncarter): Put this in a profile, once there is UI for it.
   // This specifies where to find the sync server.
   const GURL sync_service_url_;
 
-  // The last time we detected a successful transition from SYNCING state.
-  // Our backend notifies us whenever we should take a new snapshot.
-  base::Time last_synced_time_;
-
   // The time that OnConfigureStart is called. This member is zero if
   // OnConfigureStart has not yet been called, and is reset to zero once
   // OnConfigureDone is called.
   base::Time sync_configure_start_time_;
 
   // Indicates if this is the first time sync is being configured.  This value
   // is equal to !HasSyncSetupCompleted() at the time of OnBackendInitialized().
   bool is_first_time_sync_configure_;
 
   // List of available data type controllers for directory types.
@@ skipping 157 matching lines @@
   BrowsingDataRemover::Observer* browsing_data_remover_observer_;
 
   DISALLOW_COPY_AND_ASSIGN(ProfileSyncService);
 };
 
 bool ShouldShowActionOnUI(
     const syncer::SyncProtocolError& error);
 
 
 #endif  // CHROME_BROWSER_SYNC_PROFILE_SYNC_SERVICE_H_