ash: Refresh the tray items, instead of recreating them, when login status changes.

ash/system/tray/tray_image_item.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/system/tray/tray_image_item.h"
 
 #include "ash/system/tray/tray_item_view.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/gfx/image/image.h"
 #include "ui/views/controls/image_view.h"
@@ skipping 22 matching lines @@
 }
 
 views::View* TrayImageItem::CreateDefaultView(user::LoginStatus status) {
   return NULL;
 }
 
 views::View* TrayImageItem::CreateDetailedView(user::LoginStatus status) {
   return NULL;
 }
 
+void TrayImageItem::UpdateAfterLoginStatusChange(user::LoginStatus status) {
+}
+
 void TrayImageItem::DestroyTrayView() {
   tray_view_.reset();
 }
 
 void TrayImageItem::DestroyDefaultView() {
 }
 
 void TrayImageItem::DestroyDetailedView() {
 }
 
 }  // namespace internal
 }  // namespace ash