Most contentextensions tests are flaky, some of them failing a lot: http://webkit-test-results.appspot.com/dashboards/flakiness_dashboard.html#showAllRuns=true&tests=contentextensions Given that even basic-filter.html fails, this seems to be something very generic, so I'm going to mark the whole directory as flaky. Alex could reproduce some flakiness locally.
Created attachment 251170 [details] Patch
Created attachment 251172 [details] Patch
http://trac.webkit.org/changeset/183020