After http://trac.webkit.org/changeset/103890, Linux tests start passing, but Mac tests started to fail. Flakiness dashboard: http://test-results.appspot.com/dashboards/flakiness_dashboard.html#tests=plugins%2Fiframe-plugin-bgcolor.html I'm disabling this test on Mac.
Feel free to revert. I used `Tools/Scripts/webkit-patch rebaseline-expectations` to create that patch – why would that create a broken patch?
It looks mostly like a TEXT failure, so I guess mac just needs a different text baseline?
Your patch did good to Win and Linux -- they are now green. But on Mac the test timeouts frequently.