There is an incorrect casting of MediaControlMuteButtonElement to MediaControlPlayButtonElement in RenderThemeMac::paintMediaMuteButton().
Created attachment 38593 [details] patch + change log This bug does not cause any problem but is apparently incorrect.
Comment on attachment 38593 [details] patch + change log Clearing flags on attachment: 38593 Committed r47778: <http://trac.webkit.org/changeset/47778>
All reviewed patches have been landed. Closing bug.