[css-scroll-snap-1] Panning gesture should be treated as relative for last scroll direction.

[flackr]

In css-scroll-snap-1, absolute scrolls were defined to include a panning gesture released without momentum. This would lead to the scroll direction not changing while panning up/down which doesn't make much sense as from a user perspective it is a relative scroll and the user would expect it to show/hide scroll direction based ui while panning.

I think we should include panning with and without momentum as relative scrolls as this makes the most sense for all of the other implications suggested in #12394 and figure out if / how to change the snapping behavior for this special case. E.g. maybe the end of a relative scroll includes a direction hint as to whether the scroll should continue in that direction or target the end location?

@tabatkins @tursunova

[tabatkins]

Hm, yeah, I think I agree they should be treated as relative.

[tursunova]

@astearns is it possible to async resolution this issue with following proposed resolution?

Include panning with and without momentum in relative scrolls

[astearns]

The CSSWG will automatically accept this resolution one week from now if no objections are raised here. Anyone can add an emoji to this comment to express support. If you do not support this resolution, please add a new comment.

Proposed Resolution: Include panning with and without momentum in relative scrolls

[astearns]

RESOLVED: Include panning with and without momentum in relative scrolls