compositor: Allow children of layers that don't want scroll events to be scrolled.
compositor: Allow children of layers that don't want scroll events to be
scrolled.

Necessary for `overflow: scroll`.

steveklabnik/servo,RenaudParis/servo,fiji-flo/servo,KiChjang/servo,jimberlage/servo,AnthonyBroadCrawford/servo,youprofit/servo,nnethercote/servo,canaltinova/servo,jimberlage/servo,mbrubeck/servo,cbrewster/servo,saneyuki/servo,vks/servo,rentongzhang/servo,upsuper/servo,jdramani/servo,rentongzhang/servo,saneyuki/servo,avadacatavra/servo,fiji-flo/servo,dsandeephegde/servo,walac/servo,DominoTree/servo,splav/servo,saneyuki/servo,dvberkel/servo,meh/servo,DominoTree/servo,j3parker/servo,kindersung/servo,WriterOfAlicrow/servo,walac/servo,saratang/servo,walac/servo,splav/servo,thiagopnts/servo,ConnorGBrewster/servo,dati91/servo,dati91/servo,saneyuki/servo,brendandahl/servo,eddyb/servo,mattnenterprise/servo,eddyb/servo,DominoTree/servo,mattnenterprise/servo,RenaudParis/servo,peterjoel/servo,dvberkel/servo,dagnir/servo,dhananjay92/servo,larsbergstrom/servo,AnthonyBroadCrawford/servo,akosel/servo,paulrouget/servo,mdibaiee/servo,pyfisch/servo,splav/servo,mattnenterprise/servo,brendandahl/servo,kindersung/servo,huonw/servo,fiji-flo/servo,dati91/servo,notriddle/servo,jimberlage/servo,codemac/servo,rentongzhang/servo,saneyuki/servo,rnestler/servo,youprofit/servo,jdramani/servo,peterjoel/servo,peterjoel/servo,splav/servo,WriterOfAlicrow/servo,jdramani/servo,dhananjay92/servo,RenaudParis/servo,AnthonyBroadCrawford/servo,splav/servo,fiji-flo/servo,paulrouget/servo,meh/servo,sadmansk/servo,walac/servo,GyrosOfWar/servo,GyrosOfWar/servo,emilio/servo,DominoTree/servo,pyfisch/servo,runarberg/servo,runarberg/servo,thiagopnts/servo,dvberkel/servo,larsbergstrom/servo,steveklabnik/servo,mdibaiee/servo,rnestler/servo,thiagopnts/servo,avadacatavra/servo,rnestler/servo,aidanhs/servo,canaltinova/servo,rnestler/servo,anthgur/servo,wartman4404/servo,fiji-flo/servo,jimberlage/servo,mattnenterprise/servo,nrc/servo,jlegendary/servo,CJ8664/servo,mbrubeck/servo,CJ8664/servo,mattnenterprise/servo,dsandeephegde/servo,meh/servo,kindersung/servo,runarberg/servo,dvberkel/servo,jlegendary/servo,larsbergstrom/servo,jimberlage/servo,codemac/servo,zentner-kyle/servo,emilio/servo,DominoTree/servo,tafia/servo,dvberkel/servo,dati91/servo,cbrewster/servo,pyfisch/servo,paulrouget/servo,DominoTree/servo,dvberkel/servo,brendandahl/servo,eddyb/servo,caldwell/servo,szeged/servo,runarberg/servo,splav/servo,pyfisch/servo,szeged/servo,CJ8664/servo,notriddle/servo,thiagopnts/servo,kindersung/servo,szeged/servo,A-deLuna/servo,sadmansk/servo,bjwbell/servo,rnestler/servo,RenaudParis/servo,saneyuki/servo,caldwell/servo,walac/servo,peterjoel/servo,SimonSapin/servo,mbrubeck/servo,jlegendary/servo,caldwell/servo,avadacatavra/servo,mbrubeck/servo,kindersung/servo,j3parker/servo,peterjoel/servo,KiChjang/servo,jimberlage/servo,WriterOfAlicrow/servo,GyrosOfWar/servo,dagnir/servo,WriterOfAlicrow/servo,A-deLuna/servo,codemac/servo,larsbergstrom/servo,KiChjang/servo,caldwell/servo,kindersung/servo,codemac/servo,nrc/servo,saneyuki/servo,j3parker/servo,nnethercote/servo,runarberg/servo,KiChjang/servo,saratang/servo,steveklabnik/servo,RenaudParis/servo,wartman4404/servo,paulrouget/servo,aidanhs/servo,peterjoel/servo,CJ8664/servo,paulrouget/servo,CJ8664/servo,tafia/servo,larsbergstrom/servo,RenaudParis/servo,larsbergstrom/servo,jimberlage/servo,fiji-flo/servo,zentner-kyle/servo,thiagopnts/servo,caldwell/servo,ConnorGBrewster/servo,runarberg/servo,caldwell/servo,nnethercote/servo,peterjoel/servo,sadmansk/servo,huonw/servo,ConnorGBrewster/servo,tafia/servo,vks/servo,codemac/servo,SimonSapin/servo,bjwbell/servo,eddyb/servo,A-deLuna/servo,jimberlage/servo,steveklabnik/servo,splav/servo,steveklabnik/servo,nrc/servo,rentongzhang/servo,dsandeephegde/servo,rentongzhang/servo,nnethercote/servo,pyfisch/servo,tafia/servo,ConnorGBrewster/servo,emilio/servo,vks/servo,rentongzhang/servo,CJ8664/servo,dhananjay92/servo,meh/servo,anthgur/servo,jdramani/servo,fiji-flo/servo,anthgur/servo,eddyb/servo,dsandeephegde/servo,canaltinova/servo,jlegendary/servo,sadmansk/servo,walac/servo,brendandahl/servo,vks/servo,zentner-kyle/servo,dvberkel/servo,youprofit/servo,saratang/servo,wartman4404/servo,larsbergstrom/servo,zentner-kyle/servo,akosel/servo,emilio/servo,vks/servo,huonw/servo,tafia/servo,dsandeephegde/servo,aidanhs/servo,SimonSapin/servo,GyrosOfWar/servo,upsuper/servo,upsuper/servo,dagnir/servo,caldwell/servo,szeged/servo,anthgur/servo,huonw/servo,mdibaiee/servo,mdibaiee/servo,jdramani/servo,dagnir/servo,avadacatavra/servo,avadacatavra/servo,jlegendary/servo,anthgur/servo,AnthonyBroadCrawford/servo,eddyb/servo,paulrouget/servo,vks/servo,wartman4404/servo,wartman4404/servo,SimonSapin/servo,jlegendary/servo,canaltinova/servo,huonw/servo,saratang/servo,dagnir/servo,AnthonyBroadCrawford/servo,notriddle/servo,szeged/servo,ConnorGBrewster/servo,A-deLuna/servo,codemac/servo,KiChjang/servo,nnethercote/servo,aidanhs/servo,cbrewster/servo,fiji-flo/servo,sadmansk/servo,GyrosOfWar/servo,larsbergstrom/servo,codemac/servo,jimberlage/servo,zentner-kyle/servo,youprofit/servo,paulrouget/servo,WriterOfAlicrow/servo,brendandahl/servo,emilio/servo,sadmansk/servo,DominoTree/servo,saneyuki/servo,dati91/servo,saratang/servo,szeged/servo,emilio/servo,nrc/servo,eddyb/servo,upsuper/servo,sadmansk/servo,CJ8664/servo,kindersung/servo,rnestler/servo,ConnorGBrewster/servo,notriddle/servo,pyfisch/servo,dsandeephegde/servo,A-deLuna/servo,notriddle/servo,mbrubeck/servo,dhananjay92/servo,szeged/servo,mbrubeck/servo,nnethercote/servo,SimonSapin/servo,larsbergstrom/servo,saneyuki/servo,notriddle/servo,wartman4404/servo,zentner-kyle/servo,splav/servo,KiChjang/servo,youprofit/servo,anthgur/servo,meh/servo,youprofit/servo,SimonSapin/servo,dsandeephegde/servo,GyrosOfWar/servo,mattnenterprise/servo,dhananjay92/servo,AnthonyBroadCrawford/servo,zentner-kyle/servo,wartman4404/servo,splav/servo,nnethercote/servo,KiChjang/servo,A-deLuna/servo,bjwbell/servo,thiagopnts/servo,canaltinova/servo,avadacatavra/servo,nrc/servo,upsuper/servo,notriddle/servo,aidanhs/servo,aidanhs/servo,pyfisch/servo,dagnir/servo,anthgur/servo,huonw/servo,akosel/servo,jdramani/servo,dati91/servo,splav/servo,notriddle/servo,WriterOfAlicrow/servo,thiagopnts/servo,meh/servo,pyfisch/servo,DominoTree/servo,brendandahl/servo,nnethercote/servo,GyrosOfWar/servo,ConnorGBrewster/servo,aidanhs/servo,tafia/servo,peterjoel/servo,runarberg/servo,j3parker/servo,KiChjang/servo,canaltinova/servo,mdibaiee/servo,vks/servo,akosel/servo,SimonSapin/servo,dsandeephegde/servo,mattnenterprise/servo,peterjoel/servo,canaltinova/servo,eddyb/servo,cbrewster/servo,anthgur/servo,nrc/servo,cbrewster/servo,thiagopnts/servo,cbrewster/servo,upsuper/servo,RenaudParis/servo,mdibaiee/servo,akosel/servo,bjwbell/servo,rnestler/servo,saneyuki/servo,emilio/servo,szeged/servo,jlegendary/servo,saratang/servo,dhananjay92/servo,pyfisch/servo,bjwbell/servo,tafia/servo,peterjoel/servo,meh/servo,steveklabnik/servo,j3parker/servo,DominoTree/servo,huonw/servo,emilio/servo,pyfisch/servo,KiChjang/servo,emilio/servo,paulrouget/servo,CJ8664/servo,paulrouget/servo,j3parker/servo,saratang/servo,rnestler/servo,upsuper/servo,paulrouget/servo,AnthonyBroadCrawford/servo,nnethercote/servo,dati91/servo,ConnorGBrewster/servo,bjwbell/servo,notriddle/servo,WriterOfAlicrow/servo,emilio/servo,j3parker/servo,A-deLuna/servo,akosel/servo,larsbergstrom/servo,mbrubeck/servo,szeged/servo,upsuper/servo,jdramani/servo,mattnenterprise/servo,notriddle/servo,cbrewster/servo,mbrubeck/servo,mdibaiee/servo,dati91/servo,bjwbell/servo,walac/servo,sadmansk/servo,avadacatavra/servo,canaltinova/servo,szeged/servo,DominoTree/servo,dhananjay92/servo,cbrewster/servo,SimonSapin/servo,nnethercote/servo,rentongzhang/servo,steveklabnik/servo,KiChjang/servo,avadacatavra/servo,nrc/servo,youprofit/servo,brendandahl/servo,akosel/servo,dagnir/servo