Some scroll snap tests have become flaky when asynchronous. This is reproducible locally when repeating them many times, e.g. "--repeat 500 -f". tiled-drawing/scrolling/scroll-snap/scroll-snap-mandatory-borders.html tiled-drawing/scrolling/scroll-snap/scroll-snap-mandatory-overflow.html tiled-drawing/scrolling/scroll-snap/scroll-snap-mandatory-rotated.html tiled-drawing/scrolling/scroll-snap/scroll-snap-mandatory-padding.html
Also tiled-drawing/scrolling/scroll-snap/scroll-snap-iframe.html Marked as flaky in r188899.
There is a clear opportunity for a race between the end of regular scroll and the beginning of momentum scroll. Some potential approaches: - tell eventSender.callAfterScrollingCompletes whether it needs to wait for momentum scroll; - this could be automagic, because all scrolls are started via eventSender functions, and we do post the momentum scrolling events before calling eventSender.callAfterScrollingCompletes; - or it may be possible to have an eventSender function that both finishes regular scroll and starts a momentum one, or some other higher level description of a scroll that we'd use with eventSender. That way, we would keep the knowledge that there is a momentum scroll coming for longer.