Add shutdown notification and service refs to SyncServiceObserver.

components/browsing_data/core/counters/history_counter.cc

 // Copyright (c) 2015 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 "components/browsing_data/core/counters/history_counter.h"
 
 #include <limits.h>
 #include <stdint.h>
 
 #include "base/memory/ptr_util.h"
@@ skipping 140 matching lines @@
       base::MakeUnique<HistoryResult>(this, local_result_, has_synced_visits_));
 }
 
 HistoryCounter::HistoryResult::HistoryResult(const HistoryCounter* source,
                                              ResultInt value,
                                              bool has_synced_visits)
     : FinishedResult(source, value), has_synced_visits_(has_synced_visits) {}
 
 HistoryCounter::HistoryResult::~HistoryResult() {}
 
-void HistoryCounter::OnStateChanged() {
+void HistoryCounter::OnStateChanged(syncer::SyncService* sync) {
   bool history_sync_enabled_new_state = !!web_history_service_callback_.Run();
 
   // If the history sync was just enabled or disabled, restart the counter
   // so that we update the result accordingly.
   if (history_sync_enabled_ != history_sync_enabled_new_state) {
     history_sync_enabled_ = history_sync_enabled_new_state;
     Restart();
   }
 }
 
 }  // namespace browsing_data