Snap alpha for small rects

This is more similar to our alpha snapping in AAA.  More critically, we
may have a tiny alpha difference after some 90 degree rotations and that
breaks the Chromium svg layout tests (where the expected reference is a
rotated svg...)

TBR: fmalita@google.com
Bug: skia:
Change-Id: I59b750153488083f65b731643e0baca823cb78e4
Reviewed-on: https://skia-review.googlesource.com/92940
Reviewed-by: Yuqian Li <liyuqian@google.com>
Commit-Queue: Yuqian Li <liyuqian@google.com>
1 file changed