WIP: simplified display management in ash

services/ui/ws/window_server.cc

Index: services/ui/ws/window_server.cc
diff --git a/services/ui/ws/window_server.cc b/services/ui/ws/window_server.cc
index d012b886dc2f0bc50ecc2246398ff6bcdc5aef36..140df0b5c308036fd267acd92eea38d159d62dae 100644
--- a/services/ui/ws/window_server.cc
+++ b/services/ui/ws/window_server.cc
@@ -826,7 +826,10 @@ void WindowServer::OnSurfaceCreated(const cc::SurfaceInfo& surface_info) {
     window_paint_callback_.Run(window);
 
   auto* display = display_manager_->GetDisplayContaining(window);
-  if (display && window == display->GetActiveRootWindow()) {
+  const bool match1 = (display && window == display->GetActiveRootWindow());
+  const bool match2 =
+      (display && window->parent() == display->GetActiveRootWindow());
+  if (match1 || match2) {
     // A new surface for a WindowManager root has been created. This is a
     // special case because ServerWindows created by the WindowServer are not
     // part of a WindowTree. Send the SurfaceId directly to FrameGenerator and