The following layout test is flaky on platform GTK plugins/layout-in-beforeload-listener-affects-plugin-loading.html When it fails, the diff is the following: http://build.webkit.org/results/GTK%20Linux%2064-bit%20Release%20%28Tests%29/r170910%20%281308%29/plugins/layout-in-beforeload-listener-affects-plugin-loading-pretty-diff.html
Plugins are no longer supported.