reorg some path routines, preparing to switch arcs to conics
reorg some path routines, preparing to switch arcs to conics

BUG=skia:

Review URL: https://codereview.chromium.org/887783002

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