chromeos: Makes mushrome use simplified display management

ash/mus/main.cc

 // Copyright 2015 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/mus/window_manager_application.h"
 #include "services/service_manager/public/c/main.h"
 #include "services/service_manager/public/cpp/service_runner.h"
 
 MojoResult ServiceMain(MojoHandle service_request_handle) {
-  service_manager::ServiceRunner runner(new ash::mus::WindowManagerApplication);
+  const bool show_primary_host_on_connect = true;
+  ash::mus::WindowManagerApplication* app =
+      new ash::mus::WindowManagerApplication(show_primary_host_on_connect);
+  service_manager::ServiceRunner runner(app);
   return runner.Run(service_request_handle);
 }