This past spring, Willow Smith released a song called “Transparent Soul," which found her getting away from the pop-and r&b-influenced sound of her earlier work and diving headlong into punk-rock. Willow had an important collaborator along for the ride: Travis Barker, someone who's also reinvented himself over the years. He’s gone from Blink-182 drummer to songwriter to producer to label owner and, most recently, a kind of pop-punk mentor for a younger generation of artists. Willow and Barker sat down in September to talk about everything from skateboarding to the advantages of a shaved head to what they see as a rock revival in recent years.