Add shutdown notification and service refs to SyncServiceObserver.

chrome/browser/history/browsing_history_service.cc

 // Copyright 2016 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 "chrome/browser/history/browsing_history_service.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 #include <map>
@@ skipping 134 matching lines @@
     if (sync_service)
       sync_service_observer_.Add(sync_service);
   }
 }
 
 BrowsingHistoryService::~BrowsingHistoryService() {
   query_task_tracker_.TryCancelAll();
   web_history_request_.reset();
 }
 
-void BrowsingHistoryService::OnStateChanged() {
+void BrowsingHistoryService::OnStateChanged(syncer::SyncService* sync) {
   // If the history sync was enabled, start observing WebHistoryService.
   // This method should not be called after we already added the observer.
   history::WebHistoryService* web_history =
       WebHistoryServiceFactory::GetForProfile(profile_);
   if (web_history) {
     DCHECK(!web_history_service_observer_.IsObserving(web_history));
     web_history_service_observer_.Add(web_history);
     sync_service_observer_.RemoveAll();
   }
 }
@@ skipping 407 matching lines @@
   if (all_history || DeletionsDiffer(deleted_rows, urls_to_be_deleted_))
     handler_->HistoryDeleted();
 }
 
 void BrowsingHistoryService::OnWebHistoryDeleted() {
   // TODO(calamity): Only ignore web history deletions when they are actually
   // initiated by us, rather than ignoring them whenever we are deleting.
   if (!has_pending_delete_request_)
     handler_->HistoryDeleted();
 }