Elim parent_window parameter from network_connect

ash/system/chromeos/network/network_state_notifier_unittest.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/network_state_notifier.h"
 
 #include "ash/root_window_controller.h"
 #include "ash/shelf/shelf_widget.h"
 #include "ash/shell.h"
 #include "ash/system/chromeos/network/network_connect.h"
@@ skipping 75 matching lines @@
                                      base::StringValue("failure"));
     RunAllPendingInMessageLoop();
   }
 
  private:
   DISALLOW_COPY_AND_ASSIGN(NetworkStateNotifierTest);
 };
 
 TEST_F(NetworkStateNotifierTest, ConnectionFailure) {
   EXPECT_FALSE(GetSystemTray()->HasNotificationBubble());
-  ash::network_connect::ConnectToNetwork("wifi1", NULL /* owning_window */);
+  ash::network_connect::ConnectToNetwork("wifi1");
   RunAllPendingInMessageLoop();
   // Failure should spawn a notification.
   message_center::MessageCenter* message_center =
       message_center::MessageCenter::Get();
   EXPECT_TRUE(message_center->FindVisibleNotificationById(
       network_connect::kNetworkConnectNotificationId));
 }
 
 }  // namespace test
 }  // namespace ash