[PATCH] WheelHandler: smooth scroll for a greater variety of movement sizes

[PATCH] WheelHandler: smooth scroll for a greater variety of movement sizes

Duration is based on the duration and movement for 120 angle delta.
Shorten duration for smaller movements, limit duration for big movements.
We don't want fine deltas to feel extra slow and fast scrolling should still feel fast.
Minimum 3 frames for a 60hz display if delta > 2 physical pixels
(start already rendered -> 1/3 rendered -> 2/3 rendered -> end rendered).
Skip animation if <= 2 real frames for low refresh rate screens.
Otherwise, we don't scale the duration based on refresh rate or
device pixel ratio to avoid making the animation unexpectedly
longer or shorter on different screens.

BUG: 484309

Gbp-Pq: Name upstream_fb21ee82_WheelHandler-smooth-scroll-for-a-greater-variety-of-movement-sizes.patch