Update NetworkStateNotifier to use message_center.

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 <algorithm>
 #include <set>
 #include <string>
 #include <vector>
 
 #include "ash/ash_switches.h"
 #include "ash/desktop_background/desktop_background_controller.h"
 #include "ash/session_state_delegate.h"
 #include "ash/session_state_observer.h"
 #include "ash/shell.h"
 #include "ash/shell_delegate.h"
 #include "ash/shell_window_ids.h"
 #include "ash/system/bluetooth/bluetooth_observer.h"
 #include "ash/system/brightness/brightness_observer.h"
 #include "ash/system/chromeos/network/network_connect.h"
-#include "ash/system/chromeos/network/network_observer.h"
 #include "ash/system/date/clock_observer.h"
 #include "ash/system/drive/drive_observer.h"
 #include "ash/system/ime/ime_observer.h"
 #include "ash/system/logout_button/logout_button_observer.h"
 #include "ash/system/tray/system_tray.h"
 #include "ash/system/tray/system_tray_delegate.h"
 #include "ash/system/tray/system_tray_notifier.h"
 #include "ash/system/tray_accessibility.h"
 #include "ash/system/tray_caps_lock.h"
 #include "ash/system/user/update_observer.h"
@@ skipping 1292 matching lines @@
   DISALLOW_COPY_AND_ASSIGN(SystemTrayDelegate);
 };
 
 }  // namespace
 
 ash::SystemTrayDelegate* CreateSystemTrayDelegate() {
   return new chromeos::SystemTrayDelegate();
 }
 
 }  // namespace chromeos