Dunkin’ Brands Group Inc. is offering customers “contact-free delivery” of coffee, doughnuts and breakfast sandwiches through a partnership with Grubhub Inc., and the service will soon be available in Houston. The “contact-free delivery” is available at the app’s checkout section, Dunkin' (Nasdaq: DNKN) said. For orders of $10 or more through the Grubhub app, deliveries will be available for free through April 19. Most U.S.