Allow closing root window, or pressing the power button to shutdown ash_shell, and chrome /w chrome…

chrome/browser/chromeos/system/ash_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 "chrome/browser/chromeos/system/ash_system_tray_delegate.h"
 
 #include "ash/shell.h"
 #include "ash/shell_window_ids.h"
 #include "ash/system/audio/audio_observer.h"
 #include "ash/system/bluetooth/bluetooth_observer.h"
@@ skipping 349 matching lines @@
   }
 
   virtual void SetCapsLockEnabled(bool enabled) OVERRIDE {
     input_method::InputMethodManager* ime_manager =
         input_method::InputMethodManager::GetInstance();
     return ime_manager->GetXKeyboard()->SetCapsLockEnabled(enabled);
   }
 
   virtual void ShutDown() OVERRIDE {
     DBusThreadManager::Get()->GetPowerManagerClient()->RequestShutdown();
+    if (!base::chromeos::IsRunningOnChromeOS())
+      browser::AttemptUserExit();
   }
 
   virtual void SignOut() OVERRIDE {
     browser::AttemptUserExit();
   }
 
   virtual void RequestLockScreen() OVERRIDE {
     DBusThreadManager::Get()->GetSessionManagerClient()->RequestLockScreen();
   }
 
@@ skipping 873 matching lines @@
   DISALLOW_COPY_AND_ASSIGN(SystemTrayDelegate);
 };
 
 }  // namespace
 
 ash::SystemTrayDelegate* CreateSystemTrayDelegate(ash::SystemTray* tray) {
   return new chromeos::SystemTrayDelegate(tray);
 }
 
 }  // namespace chromeos