mojo events: Add |screen_location| to LocationData.

ui/events/win/events_win.cc

Index: ui/events/win/events_win.cc
diff --git a/ui/events/win/events_win.cc b/ui/events/win/events_win.cc
index 5a2c7d7e38be1e2566dbf33efeafbc3f7ff7034b..4a619cc829bd4ce74c8dfc7a1989d570a0142d11 100644
--- a/ui/events/win/events_win.cc
+++ b/ui/events/win/events_win.cc
@@ -241,9 +241,10 @@ gfx::Point EventLocationFromNative(const base::NativeEvent& native_event) {
 
 gfx::Point EventSystemLocationFromNative(
     const base::NativeEvent& native_event) {
-  // TODO(ben): Needs to always return screen position here. Returning normal
-  // origin for now since that's obviously wrong.
-  return gfx::Point(0, 0);
+  POINT global_point = { static_cast<short>(LOWORD(native_event.lParam)),
+                         static_cast<short>(HIWORD(native_event.lParam)) };
+  ClientToScreen(native_event.hwnd, &global_point);
+  return gfx::Point(global_point);
 }
 
 KeyboardCode KeyboardCodeFromNative(const base::NativeEvent& native_event) {