go.mobile/sprite/portable: bilinear fast path for *image.Uniform
go.mobile/sprite/portable: bilinear fast path for *image.Uniform

LGTM=nigeltao
R=golang-codereviews, nigeltao
CC=golang-codereviews
https://golang.org/cl/172060043

tempbottle/mobile,samanalysis/mobile,freeman0211/mobile,MaxCy330/mobile,cainiaocome/mobile,0x90sled/mobile,qskycolor/mobile,b54898533/mobile,MaxCy330/mobile,tempbottle/mobile,lonphy23t/mobile,xing/gomobile,0x90sled/mobile,samanalysis/mobile,MaxCy330/mobile,tempbottle/mobile,tempbottle/mobile,grategames/mobile,DanielWorld/mobile,steeve/mobile,xing/gomobile,steeve/mobile,MaxCy330/mobile,xing/gomobile,golang/mobile,cainiaocome/mobile,cainiaocome/mobile,ppamorim/mobile,lonphy23t/mobile,grategames/mobile,tempbottle/mobile,swisspol/mobile,0x90sled/mobile,b54898533/mobile,swisspol/mobile,zach-klippenstein/mobile,ppamorim/mobile,grategames/mobile,xing/gomobile,swisspol/mobile,qskycolor/mobile,grategames/mobile,ichu501/mobile,b54898533/mobile,zach-klippenstein/mobile,steeve/mobile,samanalysis/mobile,goldcaddy77/mobile,swisspol/mobile,ppamorim/mobile,goldcaddy77/mobile,ichu501/mobile,goldcaddy77/mobile,samanalysis/mobile,qskycolor/mobile,steeve/mobile,DanielWorld/mobile,DanielWorld/mobile,freeman0211/mobile,samanalysis/mobile,ppamorim/mobile,goldcaddy77/mobile,ichu501/mobile,lonphy23t/mobile,0x90sled/mobile,freeman0211/mobile,swisspol/mobile,cainiaocome/mobile,DanielWorld/mobile,golang/mobile,b54898533/mobile,0x90sled/mobile,xing/gomobile,lonphy23t/mobile,golang/mobile,ichu501/mobile,ichu501/mobile,b54898533/mobile,zach-klippenstein/mobile,ppamorim/mobile,MaxCy330/mobile,zach-klippenstein/mobile,goldcaddy77/mobile,golang/mobile,lonphy23t/mobile,cainiaocome/mobile,freeman0211/mobile,qskycolor/mobile