Dont pop gDM() permission UI when page is hidden on Mac

See the bug for details. This is a temporary solution until Mac UI is consistent
with other OSs for getDisplayMedia().

Bug: 920733
Change-Id: I35eac31ed048620f3d7c1cf903827fede02aa0e5
Reviewed-on: https://chromium-review.googlesource.com/c/1407639
Reviewed-by: Avi Drissman <avi@chromium.org>
Commit-Queue: Emircan Uysaler <emircan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#622360}
1 file changed