mash: Convert system tray logout button to wm common types

chrome/browser/ui/ash/system_tray_delegate_chromeos.cc

 // Copyright 2013 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_chromeos.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 #include <set>
@@ skipping 239 matching lines @@
                  weak_ptr_factory_.GetWeakPtr()));
 
   ash::WmShell::Get()->GetSessionStateDelegate()->AddSessionStateObserver(this);
 
   if (CrasAudioHandler::IsInitialized())
     CrasAudioHandler::Get()->AddAudioObserver(this);
 
   BrowserList::AddObserver(this);
 }
 
-void SystemTrayDelegateChromeOS::Shutdown() {
-}
-
 void SystemTrayDelegateChromeOS::InitializeOnAdapterReady(
     scoped_refptr<device::BluetoothAdapter> adapter) {
   bluetooth_adapter_ = adapter;
   CHECK(bluetooth_adapter_.get());
   bluetooth_adapter_->AddObserver(this);
 
   local_state_registrar_.reset(new PrefChangeRegistrar);
   local_state_registrar_->Init(g_browser_process->local_state());
 
   UpdateSessionStartTime();
@@ skipping 1052 matching lines @@
   LOG(WARNING) << "SystemTrayDelegateChromeOS::GetChildUserMessage call while "
                << "ENABLE_SUPERVISED_USERS undefined.";
   return base::string16();
 }
 
 ash::SystemTrayDelegate* CreateSystemTrayDelegate() {
   return new SystemTrayDelegateChromeOS();
 }
 
 }  // namespace chromeos