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

ash/system/network/tray_network.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/network/tray_network.h"
 
 #include "ash/shell.h"
 #include "ash/shell_window_ids.h"
 #include "ash/system/tray/system_tray.h"
 #include "ash/system/tray/system_tray_delegate.h"
@@ skipping 499 matching lines @@
 }
 
 void TrayNetwork::DestroyDefaultView() {
   default_.reset();
 }
 
 void TrayNetwork::DestroyDetailedView() {
   detailed_.reset();
 }
 
+void TrayNetwork::UpdateAfterLoginStatusChange(user::LoginStatus status) {
+}
+
 void TrayNetwork::OnNetworkRefresh(const NetworkIconInfo& info) {
   if (tray_.get())
     tray_->Update(info);
   if (default_.get())
     default_->Update();
   if (detailed_.get())
     detailed_->Update();
 }
 
 }  // namespace internal
 }  // namespace ash