Bug 287327 – [web-animations] animations without an associated timeline should have their effects in the effect stack

• Status: RESOLVED
• Resolution: FIXED
• Component: Animations

[Antoine Quint]

Prior to the addition of Scroll-driven Animations, there was no real practical purpose to set a null timeline on an animation, and in fact it wasn't possible to set one via CSS, only using the Web Animations API. With that assumption in mind, we incorrectly did not list effects associated with an animation without a timeline in the effect stack of their associated tarhet. However, with Scroll-driven Animations, the `animation-timeline` property allows to set various types of timelines (document, scroll and view) and the interaction with the `timeline-scope` property may also yield null timelines. Some new WPT tests now rely on effects associated with animations with no timelines to appear in the effect stack, so we must update our implementation to remove our timeline requirement.

[Antoine Quint]

Pull request: https://github.com/WebKit/WebKit/pull/40282

[Antoine Quint]

Submitted web-platform-tests pull request: https://github.com/web-platform-tests/wpt/pull/50593

[EWS]

Committed 290092@main (95675d2184dc): <https://commits.webkit.org/290092@main>

Reviewed commits have been landed. Closing PR #40282 and removing active labels.

[Radar WebKit Bug Importer]

<rdar://problem/144449529>