Demonstrate external-window-mode in mus-demo

services/ui/ws/window_server_delegate.h

Index: services/ui/ws/window_server_delegate.h
diff --git a/services/ui/ws/window_server_delegate.h b/services/ui/ws/window_server_delegate.h
index 802dbd77dd69f44d42898cac949265ab622c6fda..cc504a3766ad96ad9a40a961c38f1ef07d6c16d2 100644
--- a/services/ui/ws/window_server_delegate.h
+++ b/services/ui/ws/window_server_delegate.h
@@ -37,7 +37,7 @@ class WindowServerDelegate {
   };
 
   // WindowServer signal that display initialization can start.
-  virtual void StartDisplayInit() = 0;
+  virtual void StartDisplayInit(bool window_manager_connected) = 0;
 
   // Called once when the AcceleratedWidget of a Display is available.
   virtual void OnFirstDisplayReady();