Don't let neighboring radii in GrAAFillRRectOp get too close
Don't let neighboring radii in GrAAFillRRectOp get too close

Since each corner uses a different reference point, it's possible that
FP rounding can cause the edges of very close radii on a common edge
to accidentally overlap. This can cause a pixel to be drawn/blended
more than once. This CL addresses the issue by not allowing
neighboring radii on a common edge to get closer than 1/16 pixel from
one another.

Bug: skia:8562
Change-Id: Ifda97c9a4c3973405f86f7fc6846a4073b3ab581
Reviewed-on: https://skia-review.googlesource.com/c/173036
Commit-Queue: Chris Dalton <ef7fc3a08ada7d31f16e9a18b5f3c728256e041e@google.com>
Reviewed-by: Jim Van Verth <509afb0bfbb23ecaaf1fb3323209f531b45e75a6@google.com>

HalCanary/skia-hc,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,HalCanary/skia-hc,aosp-mirror/platform_external_skia,google/skia,HalCanary/skia-hc,Hikari-no-Tenshi/android_external_skia,HalCanary/skia-hc,rubenvb/skia,Hikari-no-Tenshi/android_external_skia,aosp-mirror/platform_external_skia,google/skia,aosp-mirror/platform_external_skia,rubenvb/skia,rubenvb/skia,google/skia,Hikari-no-Tenshi/android_external_skia,rubenvb/skia,google/skia,google/skia,google/skia,google/skia,google/skia,HalCanary/skia-hc,Hikari-no-Tenshi/android_external_skia,HalCanary/skia-hc,google/skia,rubenvb/skia,aosp-mirror/platform_external_skia,rubenvb/skia,aosp-mirror/platform_external_skia,rubenvb/skia,rubenvb/skia,HalCanary/skia-hc,HalCanary/skia-hc,Hikari-no-Tenshi/android_external_skia,google/skia,aosp-mirror/platform_external_skia,rubenvb/skia,Hikari-no-Tenshi/android_external_skia,Hikari-no-Tenshi/android_external_skia,HalCanary/skia-hc,Hikari-no-Tenshi/android_external_skia,rubenvb/skia,aosp-mirror/platform_external_skia,HalCanary/skia-hc