mash: Convert system tray logout button to wm common types

ash/common/system/tray/system_tray_delegate.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 "ash/common/system/tray/system_tray_delegate.h"
 
 namespace ash {
 
 NetworkIconInfo::NetworkIconInfo()
     : connecting(false),
@@ skipping 24 matching lines @@
       factory_reset_required(false) {}
 
 UpdateInfo::~UpdateInfo() {}
 
 SystemTrayDelegate::SystemTrayDelegate() {}
 
 SystemTrayDelegate::~SystemTrayDelegate() {}
 
 void SystemTrayDelegate::Initialize() {}
 
-void SystemTrayDelegate::Shutdown() {}
-
 bool SystemTrayDelegate::GetTrayVisibilityOnStartup() {
   return false;
 }
 
 LoginStatus SystemTrayDelegate::GetUserLoginStatus() const {
   return LoginStatus::NOT_LOGGED_IN;
 }
 
 void SystemTrayDelegate::ChangeProfilePicture() {}
 
@@ skipping 173 matching lines @@
     ShutdownPolicyObserver* observer) {}
 
 void SystemTrayDelegate::ShouldRebootOnShutdown(
     const RebootOnShutdownCallback& callback) {}
 
 VPNDelegate* SystemTrayDelegate::GetVPNDelegate() const {
   return nullptr;
 }
 
 }  // namespace ash