style: Use faster check to determine whether a StyleChildrenIterator is needed.
style: Use faster check to determine whether a StyleChildrenIterator is needed.

MozReview-Commit-ID: KNmdtnlEmfc

mbrubeck/servo,canaltinova/servo,mattnenterprise/servo,dati91/servo,dati91/servo,notriddle/servo,szeged/servo,anthgur/servo,peterjoel/servo,DominoTree/servo,notriddle/servo,jimberlage/servo,avadacatavra/servo,eddyb/servo,jimberlage/servo,saneyuki/servo,dsandeephegde/servo,saneyuki/servo,saneyuki/servo,dati91/servo,jimberlage/servo,splav/servo,DominoTree/servo,canaltinova/servo,anthgur/servo,larsbergstrom/servo,cbrewster/servo,peterjoel/servo,notriddle/servo,rnestler/servo,emilio/servo,ConnorGBrewster/servo,sadmansk/servo,SimonSapin/servo,thiagopnts/servo,fiji-flo/servo,fiji-flo/servo,thiagopnts/servo,saneyuki/servo,sadmansk/servo,cbrewster/servo,paulrouget/servo,jimberlage/servo,CJ8664/servo,thiagopnts/servo,rnestler/servo,DominoTree/servo,CJ8664/servo,szeged/servo,CJ8664/servo,CJ8664/servo,KiChjang/servo,nnethercote/servo,notriddle/servo,ConnorGBrewster/servo,splav/servo,thiagopnts/servo,paulrouget/servo,SimonSapin/servo,sadmansk/servo,szeged/servo,emilio/servo,jimberlage/servo,dati91/servo,emilio/servo,KiChjang/servo,avadacatavra/servo,upsuper/servo,larsbergstrom/servo,upsuper/servo,szeged/servo,splav/servo,upsuper/servo,fiji-flo/servo,upsuper/servo,notriddle/servo,eddyb/servo,cbrewster/servo,mbrubeck/servo,dati91/servo,splav/servo,pyfisch/servo,dsandeephegde/servo,paulrouget/servo,szeged/servo,saneyuki/servo,canaltinova/servo,pyfisch/servo,paulrouget/servo,KiChjang/servo,sadmansk/servo,rnestler/servo,thiagopnts/servo,splav/servo,peterjoel/servo,jimberlage/servo,SimonSapin/servo,larsbergstrom/servo,nnethercote/servo,anthgur/servo,peterjoel/servo,eddyb/servo,eddyb/servo,cbrewster/servo,peterjoel/servo,ConnorGBrewster/servo,DominoTree/servo,anthgur/servo,larsbergstrom/servo,cbrewster/servo,eddyb/servo,dsandeephegde/servo,szeged/servo,SimonSapin/servo,anthgur/servo,peterjoel/servo,KiChjang/servo,peterjoel/servo,notriddle/servo,mbrubeck/servo,mattnenterprise/servo,dsandeephegde/servo,thiagopnts/servo,anthgur/servo,larsbergstrom/servo,dsandeephegde/servo,mbrubeck/servo,splav/servo,dati91/servo,upsuper/servo,SimonSapin/servo,paulrouget/servo,nnethercote/servo,peterjoel/servo,rnestler/servo,mbrubeck/servo,dati91/servo,peterjoel/servo,larsbergstrom/servo,ConnorGBrewster/servo,szeged/servo,dati91/servo,pyfisch/servo,rnestler/servo,notriddle/servo,cbrewster/servo,szeged/servo,mattnenterprise/servo,KiChjang/servo,saneyuki/servo,avadacatavra/servo,emilio/servo,peterjoel/servo,avadacatavra/servo,notriddle/servo,pyfisch/servo,anthgur/servo,larsbergstrom/servo,sadmansk/servo,fiji-flo/servo,ConnorGBrewster/servo,paulrouget/servo,upsuper/servo,avadacatavra/servo,pyfisch/servo,DominoTree/servo,DominoTree/servo,splav/servo,CJ8664/servo,saneyuki/servo,paulrouget/servo,rnestler/servo,pyfisch/servo,KiChjang/servo,paulrouget/servo,szeged/servo,ConnorGBrewster/servo,fiji-flo/servo,canaltinova/servo,DominoTree/servo,dsandeephegde/servo,emilio/servo,fiji-flo/servo,CJ8664/servo,splav/servo,sadmansk/servo,rnestler/servo,saneyuki/servo,nnethercote/servo,KiChjang/servo,canaltinova/servo,avadacatavra/servo,avadacatavra/servo,paulrouget/servo,DominoTree/servo,pyfisch/servo,nnethercote/servo,nnethercote/servo,DominoTree/servo,mbrubeck/servo,ConnorGBrewster/servo,mattnenterprise/servo,CJ8664/servo,larsbergstrom/servo,jimberlage/servo,jimberlage/servo,mattnenterprise/servo,nnethercote/servo,DominoTree/servo,anthgur/servo,avadacatavra/servo,mattnenterprise/servo,notriddle/servo,pyfisch/servo,canaltinova/servo,sadmansk/servo,eddyb/servo,nnethercote/servo,upsuper/servo,KiChjang/servo,larsbergstrom/servo,nnethercote/servo,paulrouget/servo,fiji-flo/servo,larsbergstrom/servo,SimonSapin/servo,nnethercote/servo,SimonSapin/servo,KiChjang/servo,thiagopnts/servo,KiChjang/servo,saneyuki/servo,mattnenterprise/servo,ConnorGBrewster/servo,thiagopnts/servo,dsandeephegde/servo,eddyb/servo,pyfisch/servo,jimberlage/servo,fiji-flo/servo,SimonSapin/servo,mbrubeck/servo,notriddle/servo,emilio/servo,canaltinova/servo,dsandeephegde/servo,mattnenterprise/servo,sadmansk/servo,emilio/servo,eddyb/servo,splav/servo,emilio/servo,mbrubeck/servo,emilio/servo,cbrewster/servo,upsuper/servo,cbrewster/servo,emilio/servo,splav/servo,szeged/servo,CJ8664/servo,rnestler/servo,pyfisch/servo,canaltinova/servo,saneyuki/servo