For example, @keyframes anim { from { color: red } to { color: green } } on current gecko, getKeyframes() returns rgb(255, 0, 0) and rgb(0, 128, 0) respectively. Whereas on stylo getKeyframes() returns 'red' and 'green'. On the other hand, element.animate({ color: ['red', 'green'] }, 1000); on current gecko, getKeyframes() returns 'red' and 'green'. IIRC, current gecko returns computed values for css animation because of css variable(?). file_keyframeeffect-getkeyframes.html has a bunch of test cases that rely on current gecko behavior, but all test cases in the file does not aim to check computed values. So I'd suggest to replace keyword color with rgb() colors in the test file.

I and Brian discussed about early this week and we agreed that we should change keyword color value to rgb color in the test case.

Comment on attachment 8862732 [details] Bug 1358353 - Use rgb value instead of keyword colors. https://reviewboard.mozilla.org/r/134598/#review137586 LGTM

Pushed by hikezoe@mozilla.com: https://hg.mozilla.org/integration/autoland/rev/42e64e0c808f Use rgb value instead of keyword colors. r=boris