Remove orphaned SkImageDecoder::Target.
Remove orphaned SkImageDecoder::Target.

This was used by an experimental method on SkImageDecoder, which no
longer exists.

Review URL: https://codereview.chromium.org/760923003

shahrzadmn/skia,jtg-gg/skia,MinimalOS-AOSP/platform_external_skia,TeamExodus/external_skia,AOSPB/external_skia,w3nd1go/android_external_skia,nfxosp/platform_external_skia,TeamTwisted/external_skia,UBERMALLOW/external_skia,PAC-ROM/android_external_skia,qrealka/skia-hc,MinimalOS-AOSP/platform_external_skia,DiamondLovesYou/skia-sys,Igalia/skia,TeamTwisted/external_skia,google/skia,jtg-gg/skia,vanish87/skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,Jichao/skia,scroggo/skia,shahrzadmn/skia,pcwalton/skia,BrokenROM/external_skia,tmpvar/skia.cc,TeamExodus/external_skia,shahrzadmn/skia,MarshedOut/android_external_skia,MonkeyZZZZ/platform_external_skia,amyvmiwei/skia,w3nd1go/android_external_skia,TeamTwisted/external_skia,OneRom/external_skia,noselhq/skia,Hikari-no-Tenshi/android_external_skia,aosp-mirror/platform_external_skia,samuelig/skia,HalCanary/skia-hc,ominux/skia,invisiblek/android_external_skia,aosp-mirror/platform_external_skia,YUPlayGodDev/platform_external_skia,TeamExodus/external_skia,Jichao/skia,nvoron23/skia,MinimalOS-AOSP/platform_external_skia,MarshedOut/android_external_skia,w3nd1go/android_external_skia,qrealka/skia-hc,boulzordev/android_external_skia,YUPlayGodDev/platform_external_skia,noselhq/skia,AOSPB/external_skia,OneRom/external_skia,pcwalton/skia,boulzordev/android_external_skia,Infinitive-OS/platform_external_skia,ominux/skia,nvoron23/skia,nfxosp/platform_external_skia,UBERMALLOW/external_skia,Hikari-no-Tenshi/android_external_skia,timduru/platform-external-skia,HalCanary/skia-hc,amyvmiwei/skia,chenlian2015/skia_from_google,MinimalOS-AOSP/platform_external_skia,Infinitive-OS/platform_external_skia,AOSP-YU/platform_external_skia,AOSP-YU/platform_external_skia,pcwalton/skia,google/skia,jtg-gg/skia,YUPlayGodDev/platform_external_skia,OneRom/external_skia,VRToxin-AOSP/android_external_skia,MonkeyZZZZ/platform_external_skia,DiamondLovesYou/skia-sys,UBERMALLOW/external_skia,VRToxin-AOSP/android_external_skia,AOSP-YU/platform_external_skia,ominux/skia,Hikari-no-Tenshi/android_external_skia,VRToxin-AOSP/android_external_skia,Igalia/skia,spezi77/android_external_skia,samuelig/skia,jtg-gg/skia,AOSP-YU/platform_external_skia,MonkeyZZZZ/platform_external_skia,w3nd1go/android_external_skia,samuelig/skia,chenlian2015/skia_from_google,tmpvar/skia.cc,YUPlayGodDev/platform_external_skia,geekboxzone/mmallow_external_skia,TeamTwisted/external_skia,vanish87/skia,Infinitive-OS/platform_external_skia,MinimalOS-AOSP/platform_external_skia,invisiblek/android_external_skia,TeamExodus/external_skia,Infinitive-OS/platform_external_skia,vanish87/skia,geekboxzone/mmallow_external_skia,aosp-mirror/platform_external_skia,DiamondLovesYou/skia-sys,UBERMALLOW/external_skia,OneRom/external_skia,chenlian2015/skia_from_google,geekboxzone/mmallow_external_skia,spezi77/android_external_skia,UBERMALLOW/external_skia,MinimalOS-AOSP/platform_external_skia,AOSP-YU/platform_external_skia,boulzordev/android_external_skia,aosp-mirror/platform_external_skia,samuelig/skia,MarshedOut/android_external_skia,w3nd1go/android_external_skia,AOSP-YU/platform_external_skia,nvoron23/skia,Igalia/skia,nfxosp/platform_external_skia,BrokenROM/external_skia,amyvmiwei/skia,nvoron23/skia,spezi77/android_external_skia,todotodoo/skia,BrokenROM/external_skia,Infinitive-OS/platform_external_skia,geekboxzone/mmallow_external_skia,MarshedOut/android_external_skia,MinimalOS-AOSP/platform_external_skia,timduru/platform-external-skia,PAC-ROM/android_external_skia,AOSPB/external_skia,amyvmiwei/skia,MinimalOS-AOSP/platform_external_skia,ominux/skia,samuelig/skia,VRToxin-AOSP/android_external_skia,BrokenROM/external_skia,invisiblek/android_external_skia,shahrzadmn/skia,invisiblek/android_external_skia,invisiblek/android_external_skia,google/skia,vanish87/skia,amyvmiwei/skia,boulzordev/android_external_skia,TeamExodus/external_skia,tmpvar/skia.cc,Infinitive-OS/platform_external_skia,YUPlayGodDev/platform_external_skia,nfxosp/platform_external_skia,TeamExodus/external_skia,HalCanary/skia-hc,boulzordev/android_external_skia,MonkeyZZZZ/platform_external_skia,DiamondLovesYou/skia-sys,AOSPB/external_skia,boulzordev/android_external_skia,spezi77/android_external_skia,qrealka/skia-hc,todotodoo/skia,nfxosp/platform_external_skia,pcwalton/skia,VRToxin-AOSP/android_external_skia,AOSP-YU/platform_external_skia,AOSP-YU/platform_external_skia,pcwalton/skia,UBERMALLOW/external_skia,shahrzadmn/skia,w3nd1go/android_external_skia,Hikari-no-Tenshi/android_external_skia,UBERMALLOW/external_skia,Infinitive-OS/platform_external_skia,vanish87/skia,vanish87/skia,VRToxin-AOSP/android_external_skia,Infinitive-OS/platform_external_skia,TeamTwisted/external_skia,tmpvar/skia.cc,MonkeyZZZZ/platform_external_skia,TeamTwisted/external_skia,timduru/platform-external-skia,HalCanary/skia-hc,pcwalton/skia,MonkeyZZZZ/platform_external_skia,AOSPB/external_skia,ominux/skia,PAC-ROM/android_external_skia,shahrzadmn/skia,w3nd1go/android_external_skia,todotodoo/skia,chenlian2015/skia_from_google,DiamondLovesYou/skia-sys,Igalia/skia,amyvmiwei/skia,OneRom/external_skia,PAC-ROM/android_external_skia,todotodoo/skia,w3nd1go/android_external_skia,amyvmiwei/skia,TeamExodus/external_skia,HalCanary/skia-hc,OneRom/external_skia,ominux/skia,rubenvb/skia,MonkeyZZZZ/platform_external_skia,noselhq/skia,HalCanary/skia-hc,aosp-mirror/platform_external_skia,AOSPB/external_skia,nvoron23/skia,Hikari-no-Tenshi/android_external_skia,nfxosp/platform_external_skia,OneRom/external_skia,google/skia,chenlian2015/skia_from_google,rubenvb/skia,todotodoo/skia,chenlian2015/skia_from_google,samuelig/skia,rubenvb/skia,scroggo/skia,invisiblek/android_external_skia,TeamTwisted/external_skia,geekboxzone/mmallow_external_skia,Hikari-no-Tenshi/android_external_skia,pcwalton/skia,vanish87/skia,qrealka/skia-hc,todotodoo/skia,HalCanary/skia-hc,w3nd1go/android_external_skia,rubenvb/skia,YUPlayGodDev/platform_external_skia,Jichao/skia,rubenvb/skia,timduru/platform-external-skia,rubenvb/skia,noselhq/skia,PAC-ROM/android_external_skia,BrokenROM/external_skia,geekboxzone/mmallow_external_skia,noselhq/skia,geekboxzone/mmallow_external_skia,DiamondLovesYou/skia-sys,jtg-gg/skia,tmpvar/skia.cc,tmpvar/skia.cc,qrealka/skia-hc,OneRom/external_skia,amyvmiwei/skia,MarshedOut/android_external_skia,noselhq/skia,Igalia/skia,vanish87/skia,PAC-ROM/android_external_skia,samuelig/skia,spezi77/android_external_skia,Infinitive-OS/platform_external_skia,TeamTwisted/external_skia,Igalia/skia,AOSPB/external_skia,timduru/platform-external-skia,Jichao/skia,MarshedOut/android_external_skia,aosp-mirror/platform_external_skia,DiamondLovesYou/skia-sys,shahrzadmn/skia,Hikari-no-Tenshi/android_external_skia,aosp-mirror/platform_external_skia,AOSP-YU/platform_external_skia,timduru/platform-external-skia,google/skia,Jichao/skia,nfxosp/platform_external_skia,Jichao/skia,tmpvar/skia.cc,YUPlayGodDev/platform_external_skia,google/skia,geekboxzone/mmallow_external_skia,TeamTwisted/external_skia,pcwalton/skia,pcwalton/skia,Igalia/skia,nfxosp/platform_external_skia,todotodoo/skia,tmpvar/skia.cc,chenlian2015/skia_from_google,boulzordev/android_external_skia,nvoron23/skia,MarshedOut/android_external_skia,HalCanary/skia-hc,MarshedOut/android_external_skia,qrealka/skia-hc,UBERMALLOW/external_skia,scroggo/skia,qrealka/skia-hc,qrealka/skia-hc,Jichao/skia,PAC-ROM/android_external_skia,TeamExodus/external_skia,aosp-mirror/platform_external_skia,Jichao/skia,VRToxin-AOSP/android_external_skia,scroggo/skia,todotodoo/skia,HalCanary/skia-hc,BrokenROM/external_skia,google/skia,noselhq/skia,MarshedOut/android_external_skia,invisiblek/android_external_skia,nvoron23/skia,scroggo/skia,AOSPB/external_skia,samuelig/skia,Igalia/skia,ominux/skia,google/skia,YUPlayGodDev/platform_external_skia,BrokenROM/external_skia,OneRom/external_skia,todotodoo/skia,noselhq/skia,TeamExodus/external_skia,timduru/platform-external-skia,PAC-ROM/android_external_skia,ominux/skia,Hikari-no-Tenshi/android_external_skia,MinimalOS-AOSP/platform_external_skia,rubenvb/skia,rubenvb/skia,MonkeyZZZZ/platform_external_skia,vanish87/skia,google/skia,nfxosp/platform_external_skia,geekboxzone/mmallow_external_skia,google/skia,HalCanary/skia-hc,scroggo/skia,VRToxin-AOSP/android_external_skia,invisiblek/android_external_skia,ominux/skia,boulzordev/android_external_skia,boulzordev/android_external_skia,jtg-gg/skia,rubenvb/skia,scroggo/skia,tmpvar/skia.cc,shahrzadmn/skia,YUPlayGodDev/platform_external_skia,Jichao/skia,BrokenROM/external_skia,UBERMALLOW/external_skia,nvoron23/skia,VRToxin-AOSP/android_external_skia,shahrzadmn/skia,scroggo/skia,noselhq/skia,rubenvb/skia,AOSPB/external_skia,jtg-gg/skia,MonkeyZZZZ/platform_external_skia,spezi77/android_external_skia,PAC-ROM/android_external_skia,nvoron23/skia