Separate stroke-length code into static functions

These functions will allow us to handle resampling in the future,
because the logic will be moved out of the main Filter function and into
the small pieces of code that are easy to modify.

Bug: b/240168494
Test: autoninja -C out/Default events_unittests
Change-Id: I639634df001ad30977a2d07e48348af99e11e655
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3857624
Auto-Submit: Siarhei Vishniakou <svv@google.com>
Commit-Queue: Siarhei Vishniakou <svv@google.com>
Reviewed-by: Rob Schonberger <robsc@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1043971}
1 file changed