AVKit will set videoGravity to a nil string when building against iosmac
<rdar://problem/46011694>
Created attachment 354615 [details] Patch
Comment on attachment 354615 [details] Patch Clearing flags on attachment: 354615 Committed r238257: <https://trac.webkit.org/changeset/238257>
All reviewed patches have been landed. Closing bug.