[web-animations-1] Allow keyframe offsets outside the range [0,1]? #2081
Description
See issue at the end of: https://drafts.csswg.org/web-animations-1/#the-effect-value-of-a-keyframe-animation-effect
See issue at the end of: https://drafts.csswg.org/web-animations-1/#the-effect-value-of-a-keyframe-animation-effect