http://test-results.appspot.com/dashboards/flakiness_dashboard.html#tests=compositing%2Fcheckerboard.html Our attempts to rebaseline it and make it pass everywhere have failed. We need help from people who actually know what they are doing.
Alok broke the baselines with a chromium-side patch (r167870), which I think is why the dashboard looks so confusing.
http://trac.webkit.org/changeset/145269