Born in the studio, raised in the club, EDM is now poised to conquer the world By Kenneth Partridge It’s the bouncing, humming high-voltage strings that launch Nicki Minaj’s hit “Starships.” It’s the swirling, building buzz in Rihanna’s No. 1 smash “We Found Love.” It’s the driving dance groove in hits by Usher, Pitbull, Jennifer Lopez, Enrique Iglesias, Chris Brown—you can’t turn on pop radio for 10 minutes without hearing...