style: Remove DeclarationPushMode::Update and related code.
style: Remove DeclarationPushMode::Update and related code.

Bug: 1473180
Reviewed-by: emilio
MozReview-Commit-ID: 1fI5YRa54lQ

peterjoel/servo,KiChjang/servo,notriddle/servo,saneyuki/servo,ConnorGBrewster/servo,emilio/servo,emilio/servo,splav/servo,KiChjang/servo,dati91/servo,ConnorGBrewster/servo,pyfisch/servo,sadmansk/servo,ConnorGBrewster/servo,DominoTree/servo,DominoTree/servo,emilio/servo,peterjoel/servo,larsbergstrom/servo,paulrouget/servo,nnethercote/servo,saneyuki/servo,larsbergstrom/servo,splav/servo,larsbergstrom/servo,SimonSapin/servo,SimonSapin/servo,cbrewster/servo,KiChjang/servo,peterjoel/servo,dati91/servo,SimonSapin/servo,saneyuki/servo,pyfisch/servo,jimberlage/servo,nnethercote/servo,SimonSapin/servo,emilio/servo,KiChjang/servo,peterjoel/servo,KiChjang/servo,jimberlage/servo,szeged/servo,SimonSapin/servo,ConnorGBrewster/servo,jimberlage/servo,larsbergstrom/servo,pyfisch/servo,nnethercote/servo,paulrouget/servo,jimberlage/servo,cbrewster/servo,notriddle/servo,szeged/servo,dati91/servo,jimberlage/servo,notriddle/servo,paulrouget/servo,notriddle/servo,nnethercote/servo,ConnorGBrewster/servo,saneyuki/servo,szeged/servo,splav/servo,pyfisch/servo,peterjoel/servo,paulrouget/servo,splav/servo,KiChjang/servo,sadmansk/servo,DominoTree/servo,dati91/servo,ConnorGBrewster/servo,DominoTree/servo,nnethercote/servo,sadmansk/servo,saneyuki/servo,paulrouget/servo,notriddle/servo,emilio/servo,saneyuki/servo,splav/servo,sadmansk/servo,pyfisch/servo,saneyuki/servo,pyfisch/servo,cbrewster/servo,dati91/servo,jimberlage/servo,sadmansk/servo,jimberlage/servo,cbrewster/servo,DominoTree/servo,larsbergstrom/servo,nnethercote/servo,larsbergstrom/servo,splav/servo,DominoTree/servo,SimonSapin/servo,splav/servo,notriddle/servo,DominoTree/servo,paulrouget/servo,emilio/servo,nnethercote/servo,peterjoel/servo,notriddle/servo,larsbergstrom/servo,peterjoel/servo,larsbergstrom/servo,dati91/servo,pyfisch/servo,szeged/servo,sadmansk/servo,jimberlage/servo,dati91/servo,notriddle/servo,DominoTree/servo,DominoTree/servo,pyfisch/servo,larsbergstrom/servo,sadmansk/servo,notriddle/servo,szeged/servo,splav/servo,SimonSapin/servo,cbrewster/servo,DominoTree/servo,emilio/servo,sadmansk/servo,peterjoel/servo,emilio/servo,emilio/servo,cbrewster/servo,dati91/servo,saneyuki/servo,ConnorGBrewster/servo,paulrouget/servo,szeged/servo,cbrewster/servo,KiChjang/servo,paulrouget/servo,saneyuki/servo,splav/servo,peterjoel/servo,cbrewster/servo,nnethercote/servo,KiChjang/servo,emilio/servo,paulrouget/servo,szeged/servo,szeged/servo,szeged/servo,szeged/servo,jimberlage/servo,pyfisch/servo,pyfisch/servo,nnethercote/servo,splav/servo,KiChjang/servo,ConnorGBrewster/servo,paulrouget/servo,larsbergstrom/servo,peterjoel/servo,KiChjang/servo,SimonSapin/servo,saneyuki/servo,notriddle/servo,nnethercote/servo