Stop using HashCache in gfx::font.
Stop using HashCache in gfx::font.

It does not seem to make the code any more understandable.

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