We expose the KeyframeEffect.iterationComposite property as an experimental feature but don't actually do anything with it. We should finish its implementation and turn the feature on.
<rdar://problem/101423139>
Firefox ships this feature per WTP.fyi results. Chrome does not.
Pull request: https://github.com/WebKit/WebKit/pull/6812
Committed 257059@main (5c0978ea68f0): <https://commits.webkit.org/257059@main> Reviewed commits have been landed. Closing PR #6812 and removing active labels.