Optimize kWheelEventRegions checks

CL [1] introduced performance regressions in number of benchmarks.
The regression is caused by the fact of querying the value of
kWheelEventRegions flag.

This CL optimizes the querying. Most of the regressions partially or
fully reverted.

[1]https://chromium-review.googlesource.com/c/chromium/src/+/2419718

Bug: 1140321
Change-Id: Ib0cd7cfbafa0603579459e36853f993d2133a969
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2490327


Reviewed-by: vmpstr <vmpstr@chromium.org>
Reviewed-by: Sam Fortiner <samfort@microsoft.com>
Reviewed-by: Stephen Chenney <schenney@chromium.org>
Commit-Queue: Olga Gerchikov <gerchiko@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#823253}