update element mapping for paper-dropdown-menu
update element mapping for paper-dropdown-menu

PolymerLabs/polyup,googlearchive/polyup,davidmaxwaterman/polyup,PolymerLabs/polyup,googlearchive/polyup,wienczny/polyup,googlearchive/polyup,tomalec/polyup,tomalec/polyup,PolymerLabs/polyup,wienczny/polyup,davidmaxwaterman/polyup,davidmaxwaterman/polyup,tomalec/polyup,wienczny/polyup