Add NetworkHandler to own network handlers in src/chromeos/network

ash/system/chromeos/network/tray_network_state_observer.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/chromeos/network/tray_network_state_observer.h"
 
 #include <set>
 #include <string>
 
 #include "chromeos/network/network_state.h"
 #include "chromeos/network/network_state_handler.h"
 #include "third_party/cros_system_api/dbus/service_constants.h"
 
+using chromeos::NetworkHandler;
+
 namespace ash {
 namespace internal {
 
 TrayNetworkStateObserver::TrayNetworkStateObserver(Delegate* delegate)
     : delegate_(delegate) {
-  chromeos::NetworkStateHandler::Get()->AddObserver(this);
+  NetworkHandler::Get()->network_state_handler()->AddObserver(this);
 }
 
 TrayNetworkStateObserver::~TrayNetworkStateObserver() {
-  chromeos::NetworkStateHandler::Get()->RemoveObserver(this);
+  NetworkHandler::Get()->network_state_handler()->RemoveObserver(this);
 }
 
 void TrayNetworkStateObserver::NetworkManagerChanged() {
   delegate_->NetworkStateChanged(false);
 }
 
 void TrayNetworkStateObserver::NetworkListChanged() {
   delegate_->NetworkStateChanged(true);
 }
 
 void TrayNetworkStateObserver::DeviceListChanged() {
   delegate_->NetworkStateChanged(false);
 }
 
 void TrayNetworkStateObserver::DefaultNetworkChanged(
     const chromeos::NetworkState* network) {
   delegate_->NetworkStateChanged(true);
 }
 
 void TrayNetworkStateObserver::NetworkPropertiesUpdated(
     const chromeos::NetworkState* network) {
-  if (network == chromeos::NetworkStateHandler::Get()->DefaultNetwork())
+  if (network ==
+      NetworkHandler::Get()->network_state_handler()->DefaultNetwork())
     delegate_->NetworkStateChanged(true);
   delegate_->NetworkServiceChanged(network);
 }
 
 }  // namespace ash
 }  // namespace internal