It appears that r186689 for Bug 146855 may have caused fast/frames/frame-limit.html to start timing out on Mavericks {Release,Debug} WK2 bots: <https://webkit-test-results.appspot.com/dashboards/flakiness_dashboard.html#showAllRuns=true&revision=186689&tests=fast%2Fframes%2Fframe-limit.html>
Committed r186710 to mark the test as timing out: <http://trac.webkit.org/r186710>
Patch rolled out in <http://trac.webkit.org/changeset/186714>.