[Touchpad] Support fling to cancel swipe-to-navigate

Support canceling horizontal swipe gestures by flinging back in the
opposite direction of navigation. In crbug.com/491001724#comment26, we
have tested on different cancellation thresholds, and discussed with the
UX that the best cancellation threshold for horizontal swipe is 500.

Before: https://screencast.googleplex.com/cast/NTM1OTgyMzMyNjU0Mzg3Mnw0MjMwNmQ4ZS0xYw
After: https://screencast.googleplex.com/cast/NDUzMjMxMzAxNzgxMDk0NHxhYmVlNDFjNi1iNw
Bug: 491001724
Change-Id: I21a32ff1b321bcba6b851089c8d0bd3e96b9b88f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/7849875
Reviewed-by: Grace Cham <hscham@chromium.org>
Commit-Queue: Fuhsin Liao <fuhsinliao@google.com>
Reviewed-by: Wenyu Fu <wenyufu@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1642211}