Always use MediaPlayback audio category when playing to AppleTV or behind lock screen
<rdar://problem/42497809>
Created attachment 346282 [details] Proposed patch.
Created attachment 346285 [details] Proposed patch.
Comment on attachment 346285 [details] Proposed patch. Clearing flags on attachment: 346285 Committed r234469: <https://trac.webkit.org/changeset/234469>
All reviewed patches have been landed. Closing bug.