The following layout test is failing on GTK since it was added on r174402 <http://trac.webkit.org/changeset/174402> media/video-controls-audiotracks-trackmenu.html The diff is the following: https://build.webkit.org/results/GTK%20Linux%2064-bit%20Release%20%28Tests%29/r174402%20%283304%29/media/video-controls-audiotracks-trackmenu-pretty-diff.html
I marked this tests as failing on the GTK TestExpectations on r174685 <http://trac.webkit.org/r174685>. Please remove it from the expectation file when fixing this bug.