[Sync] Require ProfileSyncService to have an uninitialized backend on shutdown

chrome/browser/sync/profile_sync_service_session_unittest.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 <map>
 #include <string>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/callback.h"
@@ skipping 182 matching lines @@
       case chrome::NOTIFICATION_SYNC_REFRESH_LOCAL:
         notified_of_refresh_ = true;
         break;
       default:
         NOTREACHED();
         break;
     }
   }
 
   virtual void TearDown() {
+    sync_service_->Shutdown();
     sync_service_.reset();
     profile()->ResetRequestContext();
 
     // We need to destroy the profile before shutting down the threads, because
     // some of the ref counted objects in the profile depend on their
     // destruction on the io thread.
     DestroyBrowserAndProfile();
     set_profile(NULL);
 
     // Pump messages posted by the sync core thread (which may end up
@@ skipping 982 matching lines @@
     sync_pb::SessionSpecifics specifics;
     header.SetSessionSpecifics(specifics);
   }
   // Ensure we associate properly despite the pre-existing node with our local
   // tag.
   error = model_associator_->AssociateModels();
   ASSERT_FALSE(error.IsSet());
 }
 
 }  // namespace browser_sync