Much of the timing API has been changed in the spec and we need to implement these two new methods: https://drafts.csswg.org/web-animations/#dom-animationeffect-gettiming https://drafts.csswg.org/web-animations/#dom-animationeffect-updatetiming
<rdar://problem/41000677>
https://trac.webkit.org/changeset/237853/webkit