mus: Implement ScreenMus::GetCursorScreenPoint().

components/mus/ws/event_dispatcher_delegate.h

Index: components/mus/ws/event_dispatcher_delegate.h
diff --git a/components/mus/ws/event_dispatcher_delegate.h b/components/mus/ws/event_dispatcher_delegate.h
index a762df51a8ff2c25e20a7d1ae72f21b0eb390f6d..91a667a21ec3f95aaafe95c498661a9f3d5d8743 100644
--- a/components/mus/ws/event_dispatcher_delegate.h
+++ b/components/mus/ws/event_dispatcher_delegate.h
@@ -35,6 +35,10 @@ class EventDispatcherDelegate {
   // ReleaseNativeCapture is invoked if appropriate.
   virtual void OnServerWindowCaptureLost(ServerWindow* window) = 0;
 
+  // Called when the screen location of the mouse cursor has changed. Used to
+  // update clients about the global screen state.
+  virtual void OnMouseCursorLocationChanged(const gfx::Point& location) = 0;
+
   // |in_nonclient_area| is true if the event occurred in the non-client area.
   virtual void DispatchInputEventToWindow(ServerWindow* target,
                                           bool in_nonclient_area,