shiny/driver: repace style mask and event constants deprecated since OSX 10.12

Fixes golang/go#17413.

Change-Id: I4cc8a980fc1d6a45ceef48b282baa7a94663ae10
Reviewed-on: https://go-review.googlesource.com/31539
Reviewed-by: David Crawshaw <crawshaw@golang.org>
1 file changed