MacViews: Implement basic NSEvent -> ui::Event conversion for Mac

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 7b559a6ea27388cc3228ea1a3058f62960ff9fc5..a192af8a90bb1a1565d544992726ff6cfbcc5cdb 100644
--- a/ui/events/win/events_win.cc
+++ b/ui/events/win/events_win.cc
@@ -279,6 +279,13 @@ gfx::Vector2d GetMouseWheelOffset(const base::NativeEvent& native_event) {
   return gfx::Vector2d(GET_WHEEL_DELTA_WPARAM(native_event.wParam), 0);
 }
 
+base::NativeEvent CopyNativeEvent(const base::NativeEvent& event) {
+  return event;
+}
+
+void ReleaseCopiedNativeEvent(const base::NativeEvent& event) {
+}
+
 void ClearTouchIdIfReleased(const base::NativeEvent& xev) {
   NOTIMPLEMENTED();
 }