css3/compositing/isolation-isolate-blended-child.html fails every time on Mac 10.8 Debug WK2 bot:
Updated TestExpectations in <http://trac.webkit.org/r164850>.
This is rather odd. The math behind the test is in order. It might be an issue related to CG.
This failure is related to this bug: https://bugs.webkit.org/show_bug.cgi?id=130582 ([CSS Blending] Wrong color result for basic blend modes)
This doesn't seem to happen any more, according to flakiness dashboard.