Add integraton test for sync backup/rollback.

sync/engine/sync_scheduler_impl.cc

 // 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.
 
 #include "sync/engine/sync_scheduler_impl.h"
 
 #include <algorithm>
 #include <cstring>
 
 #include "base/auto_reset.h"
@@ skipping 25 matching lines @@
 bool ShouldRequestEarlyExit(const SyncProtocolError& error) {
   switch (error.error_type) {
     case SYNC_SUCCESS:
     case MIGRATION_DONE:
     case THROTTLED:
     case TRANSIENT_ERROR:
       return false;
     case NOT_MY_BIRTHDAY:
     case CLEAR_PENDING:
     case DISABLED_BY_ADMIN:
+    case USER_ROLLBACK:
       // If we send terminate sync early then |sync_cycle_ended| notification
       // would not be sent. If there were no actions then |ACTIONABLE_ERROR|
       // notification wouldnt be sent either. Then the UI layer would be left
       // waiting forever. So assert we would send something.
       DCHECK_NE(error.action, UNKNOWN_ACTION);
       return true;
     case INVALID_CREDENTIAL:
       // The notification for this is handled by PostAndProcessHeaders|.
       // Server does no have to send any action for this.
       return true;
@@ skipping 854 matching lines @@
 
 #undef SDVLOG_LOC
 
 #undef SDVLOG
 
 #undef SLOG
 
 #undef ENUM_CASE
 
 }  // namespace syncer