desktop-shell: implement touch popup grabs
desktop-shell: implement touch popup grabs

Acked-by: Pekka Paalanen <0f6ae7001e34c37b02fb2c1c2573ddf8f442136a@collabora.co.uk>

Tarnyko/weston-xdg_surface_present,mchalupa/weston,giucam/weston,eyolfson/weston,sir-murray/weston,Gnurou/weston,krezovic/weston,Tarnyko/weston-xdg_surface_present,xorgy/weston,Gnurou/weston,giucam/weston,mchalupa/weston,jonnylamb/weston,Fantu/compositor-spice,Fantu/compositor-spice,xorgy/weston,eyolfson/weston,Fantu/compositor-spice,sir-murray/weston,udoprog/weston,krezovic/weston,kwm81/weston,udoprog/weston,jonnylamb/weston,kwm81/weston