auto merge of #732 : eschweic/servo/tile-grunge, r=metajack
auto merge of #732 : eschweic/servo/tile-grunge, r=metajack

Gets rid of that annoying grit that appears between tiles after zooming.

aidanhs/servo,tafia/servo,meh/servo,nerith/servo,jimberlage/servo,g-k/servo,seanmonstar/servo,luniv/servo,brendandahl/servo,tschneidereit/servo,rnestler/servo,tempbottle/servo,ruud-v-a/servo,boghison/servo,bjwbell/servo,g-k/servo,brson/servo,owaspjocur/servo,nerith/servo,splav/servo,tschneidereit/servo,pyecs/servo,steveklabnik/servo,pyfisch/servo,chotchki/servo,CJ8664/servo,dsandeephegde/servo,jgraham/servo,akosel/servo,wpgallih/servo,steveklabnik/servo,jdramani/servo,huonw/servo,notriddle/servo,cbrewster/servo,avadacatavra/servo,KiChjang/servo,brendandahl/servo,mdibaiee/servo,emilio/servo,ConnorGBrewster/servo,karlito40/servo,Shraddha512/servo,hyowon/servo,ryancanhelpyou/servo,GreenRecycleBin/servo,jlegendary/servo,fiji-flo/servo,caldwell/servo,shrenikgala/servo,wartman4404/servo,mbrubeck/servo,anthgur/servo,AnthonyBroadCrawford/servo,notriddle/servo,deokjinkim/servo,Shraddha512/servo,indykish/servo,anthgur/servo,echochamber/servo,huonw/servo,nrc/servo,dati91/servo,GreenRecycleBin/servo,dati91/servo,rixrix/servo,dati91/servo,pyecs/servo,Adenilson/prototype-viewing-distance,zentner-kyle/servo,KiChjang/servo,larsbergstrom/servo,WriterOfAlicrow/servo,s142857/servo,sadmansk/servo,DominoTree/servo,samfoo/servo,chotchki/servo,hyowon/servo,karlito40/servo,Aalhad/CanvasRenderingContext2DMozilla,thiagopnts/servo,g-k/servo,mattnenterprise/servo,hyowon/servo,dati91/servo,RenaudParis/servo,dmarcos/servo,samfoo/servo,KiChjang/servo,pgonda/servo,A-deLuna/servo,eddyb/servo,mukilan/servo,boghison/servo,brson/servo,walac/servo,nrc/servo,boghison/servo,GyrosOfWar/servo,rnestler/servo,saneyuki/servo,echochamber/servo,srbhklkrn/SERVOENGINE,kindersung/servo,jgraham/servo,peterjoel/servo,splav/servo,rentongzhang/servo,karlito40/servo,mrobinson/servo,shrenikgala/servo,upsuper/servo,upsuper/servo,samfoo/servo,DominoTree/servo,mukilan/servo,s142857/servo,rentongzhang/servo,jgraham/servo,kindersung/servo,youprofit/servo,CJ8664/servo,dsandeephegde/servo,zentner-kyle/servo,saratang/servo,dhananjay92/servo,ruud-v-a/servo,jlegendary/servo,dagnir/servo,rentongzhang/servo,brendandahl/servo,samfoo/servo,akosel/servo,avadacatavra/servo,mattnenterprise/servo,metajack/servo,rixrix/servo,karlito40/servo,cbrewster/servo,emilio/servo,canaltinova/servo,akosel/servo,notriddle/servo,mt2d2/servo,KiChjang/servo,j3parker/servo,jlegendary/servo,rixrix/servo,brendandahl/servo,metajack/servo,larsbergstrom/servo,WriterOfAlicrow/servo,mattnenterprise/servo,A-deLuna/servo,szeged/servo,A-deLuna/servo,nerith/servo,peterjoel/servo,splav/servo,froydnj/servo,KiChjang/servo,nnethercote/servo,mt2d2/servo,dagnir/servo,tafia/servo,mdibaiee/servo,deokjinkim/servo,fiji-flo/servo,zhangjunlei26/servo,caldwell/servo,jimberlage/servo,dati91/servo,zentner-kyle/servo,pyecs/servo,meh/servo,brson/servo,dmarcos/servo,nnethercote/servo,bjwbell/servo,evilpie/servo,peterjoel/servo,ConnorGBrewster/servo,WriterOfAlicrow/servo,mt2d2/servo,splav/servo,dsandeephegde/servo,vks/servo,bfrohs/servo,szeged/servo,jgraham/servo,nnethercote/servo,saneyuki/servo,fiji-flo/servo,tschneidereit/servo,mt2d2/servo,canaltinova/servo,Aalhad/CanvasRenderingContext2DMozilla,seanmonstar/servo,szeged/servo,RenaudParis/servo,snf/servo,rentongzhang/servo,thiagopnts/servo,pgonda/servo,mukilan/servo,steveklabnik/servo,sadmansk/servo,g-k/servo,youprofit/servo,dvberkel/servo,nnethercote/servo,larsbergstrom/servo,zhangjunlei26/servo,GreenRecycleBin/servo,larsbergstrom/servo,eddyb/servo,anthgur/servo,mattnenterprise/servo,larsbergstrom/servo,splav/servo,evilpie/servo,RenaudParis/servo,owaspjocur/servo,Adenilson/prototype-viewing-distance,mrobinson/servo,Shraddha512/servo,mdibaiee/servo,hyowon/servo,RenaudParis/servo,j3parker/servo,juzer10/servo,deokjinkim/servo,mattnenterprise/servo,canaltinova/servo,ConnorGBrewster/servo,avadacatavra/servo,shrenikgala/servo,boghison/servo,pyfisch/servo,mdibaiee/servo,metajack/servo,emilio/servo,rnestler/servo,froydnj/servo,saratang/servo,froydnj/servo,jdramani/servo,aweinstock314/servo,saratang/servo,snf/servo,wartman4404/servo,larsbergstrom/servo,saratang/servo,codemac/servo,ryancanhelpyou/servo,peterjoel/servo,huonw/servo,fiji-flo/servo,jimberlage/servo,dati91/servo,CJ8664/servo,aweinstock314/servo,wartman4404/servo,michaelwu/servo,srbhklkrn/SERVOENGINE,akosel/servo,juzer10/servo,wpgallih/servo,rixrix/servo,samfoo/servo,Aalhad/CanvasRenderingContext2DMozilla,dmarcos/servo,Adenilson/prototype-viewing-distance,paulrouget/servo,froydnj/servo,karlito40/servo,tschneidereit/servo,s142857/servo,owaspjocur/servo,evilpie/servo,upsuper/servo,KiChjang/servo,SimonSapin/servo,Adenilson/prototype-viewing-distance,notriddle/servo,splav/servo,paulrouget/servo,rixrix/servo,dvberkel/servo,codemac/servo,cbrewster/servo,nick-thompson/servo,boghison/servo,ruud-v-a/servo,runarberg/servo,j3parker/servo,notriddle/servo,thiagopnts/servo,A-deLuna/servo,GreenRecycleBin/servo,jlegendary/servo,peterjoel/servo,nnethercote/servo,anthgur/servo,pyecs/servo,indykish/servo,huonw/servo,pgonda/servo,CJ8664/servo,wpgallih/servo,cbrewster/servo,evilpie/servo,nrc/servo,nick-thompson/servo,vks/servo,tempbottle/servo,owaspjocur/servo,owaspjocur/servo,aidanhs/servo,bjwbell/servo,indykish/servo,pyecs/servo,meh/servo,samfoo/servo,szeged/servo,dhananjay92/servo,chotchki/servo,jimberlage/servo,aidanhs/servo,bfrohs/servo,s142857/servo,DominoTree/servo,seanmonstar/servo,huonw/servo,hyowon/servo,rixrix/servo,dati91/servo,meh/servo,rnestler/servo,nerith/servo,avadacatavra/servo,nnethercote/servo,dhananjay92/servo,luniv/servo,s142857/servo,ryancanhelpyou/servo,Aalhad/CanvasRenderingContext2DMozilla,eddyb/servo,walac/servo,deokjinkim/servo,tschneidereit/servo,j3parker/servo,jdramani/servo,luniv/servo,peterjoel/servo,paulrouget/servo,saratang/servo,tempbottle/servo,tempbottle/servo,notriddle/servo,runarberg/servo,paulrouget/servo,wpgallih/servo,pgonda/servo,jdramani/servo,wartman4404/servo,indykish/servo,dvberkel/servo,codemac/servo,bjwbell/servo,upsuper/servo,aweinstock314/servo,RenaudParis/servo,akosel/servo,vks/servo,anthgur/servo,DominoTree/servo,nrc/servo,snf/servo,youprofit/servo,brson/servo,snf/servo,GreenRecycleBin/servo,emilio/servo,metajack/servo,kindersung/servo,vks/servo,nnethercote/servo,saneyuki/servo,paulrouget/servo,meh/servo,nick-thompson/servo,seanmonstar/servo,jgraham/servo,SimonSapin/servo,thiagopnts/servo,thiagopnts/servo,saratang/servo,AnthonyBroadCrawford/servo,zhangjunlei26/servo,evilpie/servo,michaelwu/servo,aweinstock314/servo,srbhklkrn/SERVOENGINE,mdibaiee/servo,wpgallih/servo,huonw/servo,codemac/servo,shrenikgala/servo,mdibaiee/servo,evilpie/servo,jlegendary/servo,dmarcos/servo,rentongzhang/servo,dvberkel/servo,GyrosOfWar/servo,indykish/servo,ConnorGBrewster/servo,pyfisch/servo,aidanhs/servo,froydnj/servo,nrc/servo,saneyuki/servo,cbrewster/servo,AnthonyBroadCrawford/servo,larsbergstrom/servo,akosel/servo,SimonSapin/servo,pgonda/servo,eddyb/servo,bjwbell/servo,WriterOfAlicrow/servo,codemac/servo,zentner-kyle/servo,sadmansk/servo,emilio/servo,bjwbell/servo,kindersung/servo,Adenilson/prototype-viewing-distance,tempbottle/servo,rentongzhang/servo,emilio/servo,rnestler/servo,szeged/servo,runarberg/servo,walac/servo,fiji-flo/servo,cbrewster/servo,ryancanhelpyou/servo,indykish/servo,saneyuki/servo,RenaudParis/servo,upsuper/servo,tempbottle/servo,froydnj/servo,fiji-flo/servo,DominoTree/servo,jdramani/servo,aidanhs/servo,s142857/servo,nick-thompson/servo,ruud-v-a/servo,chotchki/servo,pcwalton/servo,Aalhad/CanvasRenderingContext2DMozilla,pgonda/servo,jimberlage/servo,vks/servo,rixrix/servo,SimonSapin/servo,brson/servo,echochamber/servo,Aalhad/CanvasRenderingContext2DMozilla,srbhklkrn/SERVOENGINE,mbrubeck/servo,notriddle/servo,GyrosOfWar/servo,pyfisch/servo,g-k/servo,mbrubeck/servo,pyfisch/servo,ConnorGBrewster/servo,youprofit/servo,mt2d2/servo,jdramani/servo,tafia/servo,samfoo/servo,boghison/servo,michaelwu/servo,dhananjay92/servo,caldwell/servo,peterjoel/servo,szeged/servo,mbrubeck/servo,rnestler/servo,juzer10/servo,jgraham/servo,GreenRecycleBin/servo,dati91/servo,srbhklkrn/SERVOENGINE,dsandeephegde/servo,nick-thompson/servo,caldwell/servo,pcwalton/servo,larsbergstrom/servo,mattnenterprise/servo,akosel/servo,wpgallih/servo,luniv/servo,luniv/servo,paulrouget/servo,dsandeephegde/servo,paulrouget/servo,bjwbell/servo,dagnir/servo,bfrohs/servo,s142857/servo,walac/servo,wartman4404/servo,avadacatavra/servo,indykish/servo,aweinstock314/servo,wpgallih/servo,anthgur/servo,ConnorGBrewster/servo,steveklabnik/servo,eddyb/servo,zhangjunlei26/servo,GreenRecycleBin/servo,splav/servo,avadacatavra/servo,paulrouget/servo,GyrosOfWar/servo,zentner-kyle/servo,hyowon/servo,zhangjunlei26/servo,dmarcos/servo,snf/servo,bfrohs/servo,splav/servo,ryancanhelpyou/servo,CJ8664/servo,meh/servo,sadmansk/servo,walac/servo,karlito40/servo,avadacatavra/servo,nnethercote/servo,canaltinova/servo,dsandeephegde/servo,zhangjunlei26/servo,nrc/servo,emilio/servo,dmarcos/servo,shrenikgala/servo,echochamber/servo,owaspjocur/servo,mbrubeck/servo,pgonda/servo,pcwalton/servo,SimonSapin/servo,pyfisch/servo,codemac/servo,deokjinkim/servo,kindersung/servo,dagnir/servo,srbhklkrn/SERVOENGINE,aidanhs/servo,brendandahl/servo,echochamber/servo,mukilan/servo,luniv/servo,steveklabnik/servo,emilio/servo,luniv/servo,zentner-kyle/servo,paulrouget/servo,vks/servo,AnthonyBroadCrawford/servo,upsuper/servo,peterjoel/servo,rixrix/servo,pcwalton/servo,AnthonyBroadCrawford/servo,dagnir/servo,juzer10/servo,larsbergstrom/servo,Shraddha512/servo,j3parker/servo,splav/servo,zhangjunlei26/servo,CJ8664/servo,dagnir/servo,jimberlage/servo,dmarcos/servo,metajack/servo,brendandahl/servo,caldwell/servo,dvberkel/servo,echochamber/servo,anthgur/servo,peterjoel/servo,mukilan/servo,Shraddha512/servo,DominoTree/servo,dhananjay92/servo,jlegendary/servo,michaelwu/servo,KiChjang/servo,brendandahl/servo,indykish/servo,jdramani/servo,youprofit/servo,peterjoel/servo,youprofit/servo,wpgallih/servo,indykish/servo,Shraddha512/servo,eddyb/servo,saratang/servo,pcwalton/servo,pyecs/servo,anthgur/servo,saneyuki/servo,GyrosOfWar/servo,brson/servo,emilio/servo,ConnorGBrewster/servo,huonw/servo,dagnir/servo,KiChjang/servo,A-deLuna/servo,sadmansk/servo,caldwell/servo,dvberkel/servo,meh/servo,ConnorGBrewster/servo,evilpie/servo,canaltinova/servo,mattnenterprise/servo,nerith/servo,ryancanhelpyou/servo,nerith/servo,fiji-flo/servo,jimberlage/servo,notriddle/servo,codemac/servo,avadacatavra/servo,vks/servo,WriterOfAlicrow/servo,saneyuki/servo,ruud-v-a/servo,pyfisch/servo,emilio/servo,saneyuki/servo,snf/servo,tschneidereit/servo,szeged/servo,walac/servo,szeged/servo,steveklabnik/servo,mt2d2/servo,shrenikgala/servo,kindersung/servo,GyrosOfWar/servo,fiji-flo/servo,michaelwu/servo,mdibaiee/servo,upsuper/servo,juzer10/servo,mrobinson/servo,sadmansk/servo,szeged/servo,steveklabnik/servo,pyfisch/servo,runarberg/servo,pyecs/servo,wpgallih/servo,juzer10/servo,zentner-kyle/servo,notriddle/servo,g-k/servo,tafia/servo,mbrubeck/servo,A-deLuna/servo,tschneidereit/servo,dsandeephegde/servo,pyfisch/servo,zhangjunlei26/servo,WriterOfAlicrow/servo,metajack/servo,dhananjay92/servo,paulrouget/servo,srbhklkrn/SERVOENGINE,nnethercote/servo,zhangjunlei26/servo,wartman4404/servo,runarberg/servo,walac/servo,rixrix/servo,canaltinova/servo,michaelwu/servo,jimberlage/servo,GyrosOfWar/servo,tafia/servo,eddyb/servo,SimonSapin/servo,Shraddha512/servo,shrenikgala/servo,splav/servo,runarberg/servo,wartman4404/servo,cbrewster/servo,tafia/servo,jgraham/servo,canaltinova/servo,DominoTree/servo,Adenilson/prototype-viewing-distance,nnethercote/servo,szeged/servo,chotchki/servo,AnthonyBroadCrawford/servo,j3parker/servo,nrc/servo,hyowon/servo,ruud-v-a/servo,deokjinkim/servo,rnestler/servo,sadmansk/servo,boghison/servo,thiagopnts/servo,mrobinson/servo,evilpie/servo,pcwalton/servo,evilpie/servo,SimonSapin/servo,mt2d2/servo,mbrubeck/servo,mattnenterprise/servo,SimonSapin/servo,DominoTree/servo,thiagopnts/servo,AnthonyBroadCrawford/servo,aweinstock314/servo,dsandeephegde/servo,sadmansk/servo,CJ8664/servo,deokjinkim/servo,bfrohs/servo,snf/servo,eddyb/servo,thiagopnts/servo,saneyuki/servo,dvberkel/servo,WriterOfAlicrow/servo,tafia/servo,karlito40/servo,seanmonstar/servo,jlegendary/servo,saneyuki/servo,mrobinson/servo,canaltinova/servo,aweinstock314/servo,juzer10/servo,rnestler/servo,nick-thompson/servo,caldwell/servo,ryancanhelpyou/servo,notriddle/servo,youprofit/servo,kindersung/servo,tempbottle/servo,bfrohs/servo,pyfisch/servo,DominoTree/servo,mbrubeck/servo,RenaudParis/servo,j3parker/servo,g-k/servo,larsbergstrom/servo,aidanhs/servo,CJ8664/servo,echochamber/servo,nick-thompson/servo,mukilan/servo,seanmonstar/servo,nerith/servo,rentongzhang/servo,mrobinson/servo,runarberg/servo,GreenRecycleBin/servo,A-deLuna/servo,cbrewster/servo,Adenilson/prototype-viewing-distance,DominoTree/servo,KiChjang/servo,jimberlage/servo,KiChjang/servo,upsuper/servo,GreenRecycleBin/servo,chotchki/servo,dhananjay92/servo