add gm for tricky arc

Very likely, reimplementing this routine using doubles would also
improve results, given the many divides, subtracts, and trig calls.

Bug: skia:9272
Change-Id: I78a3dd9a11a8de1c0ef7a4406a227a0b7d9aecf7
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/230123
Reviewed-by: Florin Malita <fmalita@chromium.org>
Commit-Queue: Mike Reed <reed@google.com>
2 files changed