The following layout test is flaky on Mac. animations/animation-delay-changed.html Probable cause: CONSOLE MESSAGE: line 307: InvalidAccessError: DOM Exception 15: A parameter or an operation was not supported by the underlying object.
Marked as flaky in https://trac.webkit.org/r147243.
I'm going to fix this in bug#111612. *** This bug has been marked as a duplicate of bug 111612 ***