fast/hidpi/image-srcset-png-canvas.html frequently fails with an antialiasing diff on Mavericks Debug WK1 bot only. http://build.webkit.org/results/Apple%20Mavericks%20Debug%20WK1%20(Tests)/r163877%20(2832)/fast/hidpi/image-srcset-png-canvas-diff.png http://webkit-test-results.appspot.com/dashboards/flakiness_dashboard.html#showAllRuns=true&tests=fast%2Fhidpi%2Fimage-srcset-png-canvas.html There are two bots serving this queue, and this happens on both. Perhaps some prior test affects settings?