style: Move functions related to anonymous element to GeckoElement (Bug 1390773)
style: Move functions related to anonymous element to GeckoElement (Bug 1390773)

MozReview-Commit-ID: 6LqAPM86MQC

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