Auto merge of #17406 - Gankro:with_cap, r=jdm
Auto merge of #17406 - Gankro:with_cap, r=jdm

use DisplayListBuilder::with_capacity

DO NOT MERGE until https://github.com/servo/webrender/pull/1399 has landed in Servo.

Previously webrender was reserving 1MB of space for each display list (empirically pages weighed between 100k and 10MB when I implemented this). This was problematic for gecko because they used webrender differently. This just brings Servo back to where it was.

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