Remove the 0.5 bias from the ellipse edge function. This makes coverage drop to zero before we get clipped by the rasterizer (i.e. ensures the generated ellipse is inscribed in the geometry).
Remove the 0.5 bias from the ellipse edge function. This makes coverage drop to zero before we get clipped by the rasterizer (i.e. ensures the generated ellipse is inscribed in the geometry).

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1683843006

Review URL: https://codereview.chromium.org/1683843006

google/skia,HalCanary/skia-hc,HalCanary/skia-hc,rubenvb/skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,Hikari-no-Tenshi/android_external_skia,google/skia,google/skia,Hikari-no-Tenshi/android_external_skia,qrealka/skia-hc,Hikari-no-Tenshi/android_external_skia,google/skia,rubenvb/skia,rubenvb/skia,aosp-mirror/platform_external_skia,HalCanary/skia-hc,google/skia,rubenvb/skia,Hikari-no-Tenshi/android_external_skia,rubenvb/skia,google/skia,tmpvar/skia.cc,rubenvb/skia,qrealka/skia-hc,qrealka/skia-hc,aosp-mirror/platform_external_skia,Hikari-no-Tenshi/android_external_skia,aosp-mirror/platform_external_skia,google/skia,HalCanary/skia-hc,tmpvar/skia.cc,Hikari-no-Tenshi/android_external_skia,HalCanary/skia-hc,aosp-mirror/platform_external_skia,tmpvar/skia.cc,tmpvar/skia.cc,google/skia,rubenvb/skia,tmpvar/skia.cc,google/skia,aosp-mirror/platform_external_skia,qrealka/skia-hc,tmpvar/skia.cc,HalCanary/skia-hc,rubenvb/skia,Hikari-no-Tenshi/android_external_skia,aosp-mirror/platform_external_skia,HalCanary/skia-hc,aosp-mirror/platform_external_skia,tmpvar/skia.cc,HalCanary/skia-hc,HalCanary/skia-hc,google/skia,aosp-mirror/platform_external_skia,qrealka/skia-hc,qrealka/skia-hc,Hikari-no-Tenshi/android_external_skia,qrealka/skia-hc,qrealka/skia-hc,rubenvb/skia,rubenvb/skia,tmpvar/skia.cc,HalCanary/skia-hc,tmpvar/skia.cc