Re: [csswg-drafts] [web-animations-1] Play state of an animation with an unresolved timeline (#5400)

We have precedence for the play state being restricted to the idle or paused when the timeline is explicitly null. This was captured in the following WPT test:
  * wpt/web-animations/timing-model/animations/setting-the-timeline-of-an-animation.html
      * After clearing timeline on finished animation it is idle
      * After clearing timeline on running animation it is idle
 
The expectations were updated in  https://chromium-review.googlesource.com/c/chromium/src/+/2150687; however, the expectations no longer align with the test description.  The text associated with these tests could be updated if the new behavior is in fact what we want. 

Though one can think of an animation with a null timeline as one that is always inactive, the distinction is that the animation will never tick until the timeline is changed.  In the case of scroll timelines, the inactive state is transient. 

A benefit of restoring the previous behavior for play state of a null timelines is that we then have consistent behavior across browsers.  Mutable timelines is likely to have cross browser support before scroll timelines. Having said that,  I'm OK with going either way on this, but would like to see consistency with the test expectations and descriptions.



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Received on Tuesday, 11 August 2020 13:38:56 UTC