mouse: Fix high-resolution scrolling acceleration curve

The CL fixes the scrolling speed for slow movements for high resolution
scrolling mouse. It also unifies the acceleration curve for both low-res
and high-res mice without changing the existing behaviour of low-res ones.

The same displacement at the same speed should now yield the same offset
on screen regardless of the mouse type.

TEST=Unittests; tested with the following devices:
Logitech Anywhere MX, M560, MX Master 2S, and Performance MX;
Microsoft Comfort Optical 3000
BUG=none

Change-Id: Ib283c8ae59401e28b30f576a32be4f45744e6b7c
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/gestures/+/2059625
Reviewed-by: Harry Cutts <hcutts@chromium.org>
Reviewed-by: Sean O'Brien <seobrien@chromium.org>
Tested-by: Harry Cutts <hcutts@chromium.org>
Commit-Queue: Harry Cutts <hcutts@chromium.org>
3 files changed