Fix double blend in GrAAConvexPathRenderer
Fix double blend in GrAAConvexPathRenderer

Updates GrAAConvexPathRenderer to not draw the interior fan of a
convex path when it does not exist (i.e when segment count <= 2).

TODO: We should also detect and combine colinear segments in order to
make sure we catch every case.

BUG=skia:

Review URL: https://codereview.chromium.org/1094293002

PAC-ROM/android_external_skia,w3nd1go/android_external_skia,noselhq/skia,boulzordev/android_external_skia,BrokenROM/external_skia,shahrzadmn/skia,noselhq/skia,timduru/platform-external-skia,nfxosp/platform_external_skia,aosp-mirror/platform_external_skia,VRToxin-AOSP/android_external_skia,aosp-mirror/platform_external_skia,HalCanary/skia-hc,geekboxzone/mmallow_external_skia,TeamTwisted/external_skia,HalCanary/skia-hc,rubenvb/skia,qrealka/skia-hc,google/skia,shahrzadmn/skia,geekboxzone/mmallow_external_skia,OneRom/external_skia,shahrzadmn/skia,AOSP-YU/platform_external_skia,w3nd1go/android_external_skia,aosp-mirror/platform_external_skia,AOSPB/external_skia,Infinitive-OS/platform_external_skia,Jichao/skia,noselhq/skia,AOSPB/external_skia,AOSPB/external_skia,nfxosp/platform_external_skia,PAC-ROM/android_external_skia,rubenvb/skia,YUPlayGodDev/platform_external_skia,UBERMALLOW/external_skia,TeamTwisted/external_skia,TeamExodus/external_skia,AOSPB/external_skia,nfxosp/platform_external_skia,YUPlayGodDev/platform_external_skia,AOSPB/external_skia,MonkeyZZZZ/platform_external_skia,w3nd1go/android_external_skia,google/skia,UBERMALLOW/external_skia,noselhq/skia,shahrzadmn/skia,BrokenROM/external_skia,tmpvar/skia.cc,TeamTwisted/external_skia,ominux/skia,MinimalOS-AOSP/platform_external_skia,boulzordev/android_external_skia,vanish87/skia,geekboxzone/mmallow_external_skia,UBERMALLOW/external_skia,nvoron23/skia,todotodoo/skia,w3nd1go/android_external_skia,pcwalton/skia,qrealka/skia-hc,google/skia,amyvmiwei/skia,aosp-mirror/platform_external_skia,MonkeyZZZZ/platform_external_skia,MarshedOut/android_external_skia,Jichao/skia,YUPlayGodDev/platform_external_skia,amyvmiwei/skia,geekboxzone/mmallow_external_skia,Infinitive-OS/platform_external_skia,todotodoo/skia,UBERMALLOW/external_skia,MonkeyZZZZ/platform_external_skia,boulzordev/android_external_skia,Hikari-no-Tenshi/android_external_skia,UBERMALLOW/external_skia,MonkeyZZZZ/platform_external_skia,YUPlayGodDev/platform_external_skia,TeamTwisted/external_skia,shahrzadmn/skia,PAC-ROM/android_external_skia,MarshedOut/android_external_skia,timduru/platform-external-skia,HalCanary/skia-hc,amyvmiwei/skia,AOSP-YU/platform_external_skia,nvoron23/skia,MonkeyZZZZ/platform_external_skia,google/skia,AOSP-YU/platform_external_skia,boulzordev/android_external_skia,VRToxin-AOSP/android_external_skia,aosp-mirror/platform_external_skia,MonkeyZZZZ/platform_external_skia,UBERMALLOW/external_skia,HalCanary/skia-hc,ominux/skia,TeamExodus/external_skia,MinimalOS-AOSP/platform_external_skia,timduru/platform-external-skia,aosp-mirror/platform_external_skia,pcwalton/skia,spezi77/android_external_skia,spezi77/android_external_skia,vanish87/skia,VRToxin-AOSP/android_external_skia,BrokenROM/external_skia,spezi77/android_external_skia,ominux/skia,OneRom/external_skia,shahrzadmn/skia,nvoron23/skia,HalCanary/skia-hc,nfxosp/platform_external_skia,Infinitive-OS/platform_external_skia,Jichao/skia,noselhq/skia,MonkeyZZZZ/platform_external_skia,pcwalton/skia,todotodoo/skia,ominux/skia,YUPlayGodDev/platform_external_skia,MarshedOut/android_external_skia,w3nd1go/android_external_skia,AOSP-YU/platform_external_skia,MinimalOS-AOSP/platform_external_skia,timduru/platform-external-skia,qrealka/skia-hc,MarshedOut/android_external_skia,MinimalOS-AOSP/platform_external_skia,rubenvb/skia,spezi77/android_external_skia,Jichao/skia,VRToxin-AOSP/android_external_skia,OneRom/external_skia,invisiblek/android_external_skia,vanish87/skia,nvoron23/skia,AOSPB/external_skia,nfxosp/platform_external_skia,OneRom/external_skia,aosp-mirror/platform_external_skia,ominux/skia,Hikari-no-Tenshi/android_external_skia,tmpvar/skia.cc,Jichao/skia,geekboxzone/mmallow_external_skia,AOSP-YU/platform_external_skia,google/skia,geekboxzone/mmallow_external_skia,Jichao/skia,tmpvar/skia.cc,OneRom/external_skia,VRToxin-AOSP/android_external_skia,HalCanary/skia-hc,UBERMALLOW/external_skia,todotodoo/skia,Infinitive-OS/platform_external_skia,invisiblek/android_external_skia,nfxosp/platform_external_skia,w3nd1go/android_external_skia,YUPlayGodDev/platform_external_skia,tmpvar/skia.cc,boulzordev/android_external_skia,TeamExodus/external_skia,Hikari-no-Tenshi/android_external_skia,nvoron23/skia,OneRom/external_skia,BrokenROM/external_skia,HalCanary/skia-hc,pcwalton/skia,vanish87/skia,TeamTwisted/external_skia,spezi77/android_external_skia,nfxosp/platform_external_skia,boulzordev/android_external_skia,VRToxin-AOSP/android_external_skia,nvoron23/skia,MarshedOut/android_external_skia,w3nd1go/android_external_skia,rubenvb/skia,noselhq/skia,shahrzadmn/skia,YUPlayGodDev/platform_external_skia,OneRom/external_skia,google/skia,ominux/skia,MarshedOut/android_external_skia,MarshedOut/android_external_skia,rubenvb/skia,timduru/platform-external-skia,w3nd1go/android_external_skia,qrealka/skia-hc,google/skia,vanish87/skia,MarshedOut/android_external_skia,Hikari-no-Tenshi/android_external_skia,vanish87/skia,VRToxin-AOSP/android_external_skia,ominux/skia,boulzordev/android_external_skia,Infinitive-OS/platform_external_skia,pcwalton/skia,OneRom/external_skia,pcwalton/skia,ominux/skia,TeamTwisted/external_skia,Hikari-no-Tenshi/android_external_skia,HalCanary/skia-hc,shahrzadmn/skia,TeamTwisted/external_skia,vanish87/skia,boulzordev/android_external_skia,noselhq/skia,w3nd1go/android_external_skia,nvoron23/skia,MarshedOut/android_external_skia,nfxosp/platform_external_skia,UBERMALLOW/external_skia,invisiblek/android_external_skia,VRToxin-AOSP/android_external_skia,amyvmiwei/skia,invisiblek/android_external_skia,aosp-mirror/platform_external_skia,todotodoo/skia,shahrzadmn/skia,PAC-ROM/android_external_skia,tmpvar/skia.cc,AOSP-YU/platform_external_skia,tmpvar/skia.cc,BrokenROM/external_skia,timduru/platform-external-skia,Hikari-no-Tenshi/android_external_skia,aosp-mirror/platform_external_skia,pcwalton/skia,invisiblek/android_external_skia,BrokenROM/external_skia,invisiblek/android_external_skia,todotodoo/skia,Infinitive-OS/platform_external_skia,amyvmiwei/skia,Jichao/skia,qrealka/skia-hc,OneRom/external_skia,amyvmiwei/skia,rubenvb/skia,YUPlayGodDev/platform_external_skia,HalCanary/skia-hc,AOSP-YU/platform_external_skia,AOSPB/external_skia,pcwalton/skia,rubenvb/skia,vanish87/skia,rubenvb/skia,nfxosp/platform_external_skia,invisiblek/android_external_skia,Infinitive-OS/platform_external_skia,MinimalOS-AOSP/platform_external_skia,TeamExodus/external_skia,BrokenROM/external_skia,PAC-ROM/android_external_skia,noselhq/skia,geekboxzone/mmallow_external_skia,Infinitive-OS/platform_external_skia,todotodoo/skia,Jichao/skia,YUPlayGodDev/platform_external_skia,geekboxzone/mmallow_external_skia,tmpvar/skia.cc,geekboxzone/mmallow_external_skia,TeamExodus/external_skia,VRToxin-AOSP/android_external_skia,AOSP-YU/platform_external_skia,qrealka/skia-hc,PAC-ROM/android_external_skia,MinimalOS-AOSP/platform_external_skia,qrealka/skia-hc,TeamExodus/external_skia,invisiblek/android_external_skia,google/skia,tmpvar/skia.cc,AOSPB/external_skia,todotodoo/skia,todotodoo/skia,vanish87/skia,TeamTwisted/external_skia,Hikari-no-Tenshi/android_external_skia,Hikari-no-Tenshi/android_external_skia,MonkeyZZZZ/platform_external_skia,nvoron23/skia,BrokenROM/external_skia,boulzordev/android_external_skia,pcwalton/skia,MinimalOS-AOSP/platform_external_skia,aosp-mirror/platform_external_skia,noselhq/skia,nvoron23/skia,rubenvb/skia,AOSP-YU/platform_external_skia,UBERMALLOW/external_skia,TeamExodus/external_skia,AOSPB/external_skia,spezi77/android_external_skia,Infinitive-OS/platform_external_skia,timduru/platform-external-skia,amyvmiwei/skia,MinimalOS-AOSP/platform_external_skia,MinimalOS-AOSP/platform_external_skia,tmpvar/skia.cc,PAC-ROM/android_external_skia,qrealka/skia-hc,PAC-ROM/android_external_skia,amyvmiwei/skia,Jichao/skia,TeamExodus/external_skia,MonkeyZZZZ/platform_external_skia,HalCanary/skia-hc,google/skia,rubenvb/skia,TeamExodus/external_skia,TeamTwisted/external_skia,google/skia,ominux/skia,PAC-ROM/android_external_skia