mus: Implement ScreenMus::GetCursorScreenPoint().

ui/views/mus/screen_mus.cc

Index: ui/views/mus/screen_mus.cc
diff --git a/ui/views/mus/screen_mus.cc b/ui/views/mus/screen_mus.cc
index d22499cc4b5e2dc03ee3801f10704399d576a39f..65a9147eacbfc433c80db44e7151b805671cc7cc 100644
--- a/ui/views/mus/screen_mus.cc
+++ b/ui/views/mus/screen_mus.cc
@@ -4,6 +4,7 @@
 
 #include "ui/views/mus/screen_mus.h"
 
+#include "base/threading/thread_restrictions.h"
 #include "mojo/converters/geometry/geometry_type_converters.h"
 #include "services/shell/public/cpp/connection.h"
 #include "services/shell/public/cpp/connector.h"
@@ -143,8 +144,10 @@ void ScreenMus::ProcessDisplayChanged(const gfx::Display& changed_display,
 }
 
 gfx::Point ScreenMus::GetCursorScreenPoint() {
-  NOTIMPLEMENTED();
-  return gfx::Point();
+  base::ThreadRestrictions::ScopedAllowWait allow_wait;
+  mojo::PointPtr p;
+  display_manager_->GetCursorScreenPoint(&p);
+  return p.To<gfx::Point>();
 }
 
 gfx::NativeWindow ScreenMus::GetWindowUnderCursor() {