Update NetworkStateNotifier to use message_center.

ash/system/chromeos/network/network_connect.h

 // 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.
 
 #ifndef ASH_SYSTEM_CHROMEOS_NETWORK_NETWORK_CONNECT_H
 #define ASH_SYSTEM_CHROMEOS_NETWORK_NETWORK_CONNECT_H
 
 #include <string>
 
 #include "ash/ash_export.h"
 #include "base/strings/string16.h"
 #include "ui/gfx/native_widget_types.h"  // gfx::NativeWindow
 
 namespace base {
 class DictionaryValue;
 }
 
 namespace ash {
 namespace network_connect {
 
+ASH_EXPORT extern const char kNetworkConnectNotificationId[];
+ASH_EXPORT extern const char kNetworkActivateNotificationId[];
+
 // Requests a network connection and handles any errors and notifications.
 // |owning_window| is used to parent any UI on failure (e.g. for certificate
 // enrollment). If NULL, the default window will be used.
 ASH_EXPORT void ConnectToNetwork(const std::string& service_path,
                                  gfx::NativeWindow owning_window);
 
 // Requests network activation and handles any errors and notifications.
 ASH_EXPORT void ActivateCellular(const std::string& service_path);
 
 // Determines whether or not a network requires a connection to activate or
@@ skipping 16 matching lines @@
 ASH_EXPORT base::string16 ErrorString(const std::string& error);
 
 // Shows the settings for the network specified by |service_path|. If empty,
 // or no matching network exists, shows the general internet settings page.
 ASH_EXPORT void ShowNetworkSettings(const std::string& service_path);
 
 }  // network_connect
 }  // ash
 
 #endif  // ASH_SYSTEM_CHROMEOS_NETWORK_NETWORK_CONNECT_H