When starting up or pausing/resuming data loading, always replace the AVPlayerItem on the main thread.
<rdar://problem/17507145>
Created attachment 235026 [details] Proposed patch
Comment on attachment 235026 [details] Proposed patch Clearing flags on attachment: 235026 Committed r171157: <http://trac.webkit.org/changeset/171157>
All reviewed patches have been landed. Closing bug.