Mustash: Ensure surfaces submitted to Mus by WM and embedders contain Surfaces with embeded content.

services/ui/ws/display.cc

Index: services/ui/ws/display.cc
diff --git a/services/ui/ws/display.cc b/services/ui/ws/display.cc
index e8cb98cf9d6d9958c3c41fd57445a5f9918ceb2a..406dfb77acb47dcd82b5646d3845c06882c23b15 100644
--- a/services/ui/ws/display.cc
+++ b/services/ui/ws/display.cc
@@ -270,6 +270,13 @@ ServerWindow* Display::GetRootWindow() {
   return root_.get();
 }
 
+ServerWindow* Display::GetActiveRootWindow() {
+  WindowManagerDisplayRoot* display_root = GetActiveWindowManagerDisplayRoot();
+  if (display_root)
+    return display_root->root();
+  return nullptr;
+}
+
 void Display::OnAcceleratedWidgetAvailable() {
   display_manager()->OnDisplayAcceleratedWidgetAvailable(this);
   InitWindowManagerDisplayRoots();