Abort sync cycles when download step fails

sync/sessions/status_controller.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.
 
 // StatusController handles all counter and status related number crunching and
 // state tracking on behalf of a SyncSession.  It 'controls' the model data
 // defined in session_state.h.  The most important feature of StatusController
 // is the ScopedModelSafetyRestriction. When one of these is active, the
 // underlying data set exposed via accessors is swapped out to the appropriate
 // set for the restricted ModelSafeGroup behind the scenes.  For example, if
@@ skipping 154 matching lines @@
   // Returns the number of updates received from the sync server.
   int64 CountUpdates() const;
 
   // Returns true iff any of the commit ids added during this session are
   // bookmark related, and the bookmark group restriction is in effect.
   bool HasBookmarkCommitActivity() const {
     return ActiveGroupRestrictionIncludesModel(syncable::BOOKMARKS) &&
         shared_.commit_set.HasBookmarkCommitId();
   }
 
-  // Returns true if the last download_updates_command received a valid
-  // server response.
-  bool download_updates_succeeded() const {
-    return updates_response().has_get_updates();
+  // Returns the status returned from last download updates command.
+  SyncerError last_download_updates_result() const {
+    return shared_.error.value().last_download_updates_result;
   }
 
-  // Returns true if the last updates response indicated that we were fully
-  // up to date.  This is subtle: if it's false, it could either mean that
-  // the server said there WAS more to download, or it could mean that we
-  // were unable to reach the server.  If we didn't request every enabled
-  // datatype, then we can't say for sure that there's nothing left to
-  // download: in that case, this also returns false.
-  bool ServerSaysNothingMoreToDownload() const;
-
   ModelSafeGroup group_restriction() const {
     return group_restriction_;
   }
 
   base::Time sync_start_time() const {
     // The time at which we sent the first GetUpdates command for this sync.
     return sync_start_time_;
   }
 
   // Check whether a particular model is included by the active group
@@ skipping 90 matching lines @@
   }
  private:
   StatusController* status_;
   DISALLOW_COPY_AND_ASSIGN(ScopedModelSafeGroupRestriction);
 };
 
 }
 }
 
 #endif  // SYNC_SESSIONS_STATUS_CONTROLLER_H_