Revert "Snaps after scrollbar clicking."

This reverts commit e98df9c6e2269035a9abb23ca8fd8dc906ad3d38.

Reason for revert: suspect for webkit_layout_tests consistently
failing, e.g.
https://ci.chromium.org/p/chromium/builders/luci.chromium.ci/Win7%20Tests%20%281%29/81791

Original change's description:
> Snaps after scrollbar clicking.
> 
> After user clicking on the scrollbar's track or arrows, we should snap
> to the closest snap position of the container. This is done by simply
> moving SnapAfterScrollbarDragging() from
> ScrollableArea::MouseReleasedScrollbar() up to Scrollbar::MouseUp().
> 
> This patch also rewrites the previous
> snaps-after-scrollbar-dragging.html test using the gesture-util.js, and
> adds the new clicking tests to it as well.
> 
> Bug: 860768
> Cq-Include-Trybots: luci.chromium.try:linux_layout_tests_slimming_paint_v2;master.tryserver.blink:linux_trusty_blink_rel
> Change-Id: I75267c3fc0917ecf5c14673a1eb480a047d03824
> Reviewed-on: https://chromium-review.googlesource.com/1127153
> Commit-Queue: Sandra Sun <[email protected]>
> Reviewed-by: David Bokan <[email protected]>
> Reviewed-by: Majid Valipour <[email protected]>
> Cr-Commit-Position: refs/heads/master@{#575191}

[email protected],[email protected],[email protected]

Change-Id: Iab3c3c489bda0fc6b150ba0e0a5bde8de9721798
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 860768
Cq-Include-Trybots: luci.chromium.try:linux_layout_tests_slimming_paint_v2;master.tryserver.blink:linux_trusty_blink_rel
Reviewed-on: https://chromium-review.googlesource.com/1138013
Reviewed-by: Mikel Astiz <[email protected]>
Commit-Queue: Mikel Astiz <[email protected]>
Cr-Commit-Position: refs/heads/master@{#575202}
10 files changed