Demonstrate external-window-mode in mus-demo

services/ui/service.cc

Index: services/ui/service.cc
diff --git a/services/ui/service.cc b/services/ui/service.cc
index 03de291e3202bb128d8c74cfbab6d060eae824f0..27980b09ad824c23ebd2570b56d3bc6ea00827d5 100644
--- a/services/ui/service.cc
+++ b/services/ui/service.cc
@@ -229,8 +229,11 @@ bool Service::OnConnect(const service_manager::ServiceInfo& remote_info,
   return true;
 }
 
-void Service::StartDisplayInit() {
-  platform_screen_->Init(window_server_->display_manager());
+void Service::StartDisplayInit(bool window_manager_connected) {
+  platform_screen_->Init(window_server_->display_manager(),
+                         window_manager_connected
+                             ? display::PlatformScreen::WINDOW_MODE_INTERNAL
+                             : display::PlatformScreen::WINDOW_MODE_EXTERNAL);
 }
 
 void Service::OnFirstDisplayReady() {