From @zcorpan in https://bugs.chromium.org/p/chromium/issues/detail?id=674454

I don't think we should fire any events, because I don't know how to implement it. (In Blink, in an inactive document, events are just dropped on the ground.)

Just rejecting the promise would work, though.

Also need to define what happens if the document becomes inactive between the request and the animation frame task.