media/video-rtl.html is flaky. Example: http://build.webkit.org/results/Apple%20Mavericks%20Release%20WK1%20(Tests)/r169433%20(6322)/results.html It doesn't always show the gray bar, which is the difference between the appearance of an unbuffered versus buffered video. It could be that the test needs to be rebaselined, or maybe just updated to wait until loading is complete before ending the test.
It is very flaky, failing up to 30% of time on some bots. http://webkit-test-results.appspot.com/dashboards/flakiness_dashboard.html#showAllRuns=true&tests=media%2Fvideo-rtl.html Marked as flaky in <http://trac.webkit.org/r169624>.