Clean-up of the system shutdown code paths

chrome/browser/ui/ash/system_tray_delegate_common.cc

 // Copyright 2014 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/ui/ash/system_tray_delegate_common.h"
 
 #include "ash/shell.h"
 #include "ash/shell_delegate.h"
 #include "ash/system/tray/system_tray.h"
 #include "ash/system/tray/system_tray_notifier.h"
@@ skipping 138 matching lines @@
 
 void SystemTrayDelegateCommon::ShowSupervisedUserInfo() {
 }
 
 void SystemTrayDelegateCommon::ShowEnterpriseInfo() {
 }
 
 void SystemTrayDelegateCommon::ShowUserLogin() {
 }
 
-void SystemTrayDelegateCommon::ShutDown() {
-}
-
 void SystemTrayDelegateCommon::SignOut() {
 }
 
 void SystemTrayDelegateCommon::RequestLockScreen() {
 }
 
 void SystemTrayDelegateCommon::RequestRestartForUpdate() {
   chrome::AttemptRestart();
 }
 
@@ skipping 115 matching lines @@
     const content::NotificationSource& source,
     const content::NotificationDetails& details) {
   if (type == chrome::NOTIFICATION_UPGRADE_RECOMMENDED) {
     ash::UpdateInfo info;
     GetUpdateInfo(content::Source<UpgradeDetector>(source).ptr(), &info);
     GetSystemTrayNotifier()->NotifyUpdateRecommended(info);
   } else {
     NOTREACHED();
   }
 }