Add shutdown notification and service refs to SyncServiceObserver.

ios/chrome/browser/ui/ntp/recent_tabs/synced_sessions_bridge.mm

 // Copyright 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.
 
 #import "ios/chrome/browser/ui/ntp/recent_tabs/synced_sessions_bridge.h"
 
 #include "components/browser_sync/profile_sync_service.h"
 #include "components/signin/core/browser/signin_manager.h"
 #include "components/sync/driver/sync_service.h"
 #include "ios/chrome/browser/browser_state/chrome_browser_state.h"
@@ skipping 18 matching lines @@
           IOSChromeProfileSyncServiceFactory::GetForBrowserState(browserState)),
       signin_manager_observer_(this),
       first_sync_cycle_is_completed_(false) {
   signin_manager_observer_.Add(signin_manager_);
 }
 
 SyncedSessionsObserverBridge::~SyncedSessionsObserverBridge() {}
 
 #pragma mark - SyncObserverBridge
 
-void SyncedSessionsObserverBridge::OnStateChanged() {
+void SyncedSessionsObserverBridge::OnStateChanged(syncer::SyncService* sync) {
   if (!signin_manager_->IsAuthenticated())
     first_sync_cycle_is_completed_ = false;
   [owner_ onSyncStateChanged];
 }
 
-void SyncedSessionsObserverBridge::OnSyncCycleCompleted() {
+void SyncedSessionsObserverBridge::OnSyncCycleCompleted(
+    syncer::SyncService* sync) {
   if (sync_service_->GetActiveDataTypes().Has(syncer::SESSIONS))
     first_sync_cycle_is_completed_ = true;
   [owner_ onSyncStateChanged];
 }
 
-void SyncedSessionsObserverBridge::OnSyncConfigurationCompleted() {
+void SyncedSessionsObserverBridge::OnSyncConfigurationCompleted(
+    syncer::SyncService* sync) {
   [owner_ reloadSessions];
 }
 
-void SyncedSessionsObserverBridge::OnForeignSessionUpdated() {
+void SyncedSessionsObserverBridge::OnForeignSessionUpdated(
+    syncer::SyncService* sync) {
   [owner_ reloadSessions];
 }
 
 bool SyncedSessionsObserverBridge::IsFirstSyncCycleCompleted() {
   return first_sync_cycle_is_completed_;
 }
 
 #pragma mark - SigninManagerBase::Observer
 
 void SyncedSessionsObserverBridge::GoogleSignedOut(
     const std::string& account_id,
     const std::string& username) {
   first_sync_cycle_is_completed_ = false;
   [owner_ reloadSessions];
 }
 
 }  // namespace synced_sessions