Animation.{effect|finished|ready} ship in Firefox 63

[a2sheppy]

Add indications that Animation.ready, .finished, and
.effect are now enabled by default in Firefox 63.

[Elchi3]

Intent to ship https://groups.google.com/forum/#!topic/mozilla.dev.platform/fcFctnUjs7A
Bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1476158

MDN pages this PR updates:
https://developer.mozilla.org/en-US/docs/Web/API/Animation/effect
https://developer.mozilla.org/en-US/docs/Web/API/Animation/finished
https://developer.mozilla.org/en-US/docs/Web/API/Animation/ready

@birtles does this make sense to you? r?

fwiw, these pages already have Firefox 63 set:
https://developer.mozilla.org/en-US/docs/Web/API/AnimationEffect#Browser_compatibility
https://developer.mozilla.org/en-US/docs/Web/API/KeyframeEffect
https://developer.mozilla.org/en-US/docs/Web/API/EffectTiming
(this work was done as part of https://bugzilla.mozilla.org/show_bug.cgi?id=1456394#c86)

Anything else to update for 63?

[birtles]

Thank you so much!

I haven't had a chance to thoroughly review (I'm racing out the door now) but a couple of things I noticed so far:

• KeyframeEffect.composite and KeyframeEffect.iterationComposite are not shipping yet. They are behind the dom.animations-api.compositing.enabled pref.
• Animation.timeline is not yet shipping in Firefox. It is behind the dom.animations-api.timelines.enabled pref.

Also, I've just marked https://bugzilla.mozilla.org/show_bug.cgi?id=1483404 as dev-doc-needed since that was another recent spec change.

[connorshea]

Shouldn't this go above the version_added: 48?

[Elchi3]

Thanks @a2sheppy and @birtles! This PR looks good to me now. 👍

I will follow up with the pref changes you mentioned and that were done per https://bugzilla.mozilla.org/show_bug.cgi?id=1471814 in a new PR.

[Elchi3]

I've opened #2673 and #2674 as follow-ups.