The following layout test is flaky on platform GTK media/media-fragments/TC0024.html The diff is here: http://build.webkit.org/results/GTK%20Linux%2064-bit%20Release%20%28Tests%29/r170551%20%281118%29/media/media-fragments/TC0024-pretty-diff.html
There are no references to this bug in any TestExpectations. It's probable this bug was solved at some point but it wasn't marked as closed. I'm closing this bug now. If you think this bug report is still valid, please reopen it and add an entry to TestExpectations.