It is possible for MediaSession::endInterruption to be called several times when resuming, which confuses the MediaSession state machine.
<rdar://problem/19572894>
Created attachment 246285 [details] Proposed patch
Comment on attachment 246285 [details] Proposed patch Clearing flags on attachment: 246285 Committed r179869: <http://trac.webkit.org/changeset/179869>
All reviewed patches have been landed. Closing bug.