chromeos: Refactor system tray Wi-Fi connect dialog so it works with mash

ash/mus/window_manager_application.h

Index: ash/mus/window_manager_application.h
diff --git a/ash/mus/window_manager_application.h b/ash/mus/window_manager_application.h
index 687bd1f3776c6c4e4a87f9ba084434394a3e0dc8..2347444d8b06d44dae9d3863db68f4d693a28f67 100644
--- a/ash/mus/window_manager_application.h
+++ b/ash/mus/window_manager_application.h
@@ -47,6 +47,7 @@ namespace mus {
 
 class AcceleratorRegistrarImpl;
 class NativeWidgetFactoryMus;
+class NetworkConnectDelegateMus;
 class WindowManager;
 
 // Hosts the window manager and the ash system user interface for mash.
@@ -115,8 +116,7 @@ class WindowManagerApplication
       screenlock_state_listener_binding_;
 
 #if defined(OS_CHROMEOS)
-  class StubNetworkConnectDelegate;
-  std::unique_ptr<StubNetworkConnectDelegate> network_connect_delegate_;
+  std::unique_ptr<NetworkConnectDelegateMus> network_connect_delegate_;
   std::unique_ptr<chromeos::system::ScopedFakeStatisticsProvider>
       statistics_provider_;
 #endif