Willow Smith started 2013 with the angsty, mournful “Sugar and Spice,†which was as musically far from the joyful “Whip My Hair†as possible. Now doing her musical work alongside a DJ called MVSIC in a duo called Melodic Chaotic, Willow is back to having fun. In “Summer Fling,†the youngest Smith engages in preteen-sanctioned fun including campfire dancing, speaking in a British accent, and getting pushed into a pool by her brother. The clip looks like Coachella and Instagram made an American Eagle billboard together, and the music has gone from feeling vaguely Rihanna-esque to fairly Drake-ian.