mus: Implement ScreenMus::GetCursorScreenPoint().

components/mus/ws/window_tree.h

Index: components/mus/ws/window_tree.h
diff --git a/components/mus/ws/window_tree.h b/components/mus/ws/window_tree.h
index 1bcff730c630298fe462aa95f776214377a6b7d9..f58d7b2560012cf312d3a8dbe0e2d70a4077230a 100644
--- a/components/mus/ws/window_tree.h
+++ b/components/mus/ws/window_tree.h
@@ -23,10 +23,12 @@
 #include "components/mus/ws/user_id.h"
 #include "components/mus/ws/window_tree_binding.h"
 #include "mojo/public/cpp/bindings/associated_binding.h"
+#include "ui/gfx/geometry/point.h"
 
 namespace gfx {
 class Insets;
 class Rect;
+class Point;
 }
 
 namespace ui {
@@ -373,6 +375,8 @@ class WindowTree : public mojom::WindowTree,
   void GetWindowManagerClient(
       mojo::AssociatedInterfaceRequest<mojom::WindowManagerClient> internal)
       override;
+  void GetCursorScreenPoint(const GetCursorScreenPointCallback& callback)
+      override;
 
   // mojom::WindowManagerClient:
   void AddAccelerator(uint32_t id,