http://test-results.appspot.com/dashboards/flakiness_dashboard.html#group=%40ToT%20-%20webkit.org&tests=media%2Fmedia-captions.html Maybe http://trac.webkit.org/changeset/142809 ?
Added a crash test expectation in http://trac.webkit.org/changeset/142930.
<rdar://problem/13220535>
Marking this as a dup of https://bugs.webkit.org/show_bug.cgi?id=109886 because that had a crash log. *** This bug has been marked as a duplicate of bug 109886 ***