This test relies on triggering a transition on the 'color' property which,
at least when this test was written, would trigger a transition on the
-webkit-text-fill-color property since its default value is 'currentcolor'.
However, in crashtests.list we turn off layout.css.prefixes.webkit so
we should not trigger a transition on -webkit-test-fill-color.
This test exercises some code that, prior to this bug, would fail because we
would initially create the transition on -webkit-test-fill-color (because we
forgot to check if it was enabled or not) and then we would call other
methods that *do* check for the enabled-ness of the property leaving us
in an unexpected state.
<body style="transition: all 4s" onload="document.body.style.color = 'green';"></body>