This is what you came for: the hottest hits of 2016, including Sia’s boastful “The Greatest,” Britney Spears’ lightly playful “Make Me…,” and Flume’s whirling, throbbing “Never Be Like You.” This edition of the long-running NOW series shows how pop artists are borrowing ideas from one another, with rock stalwarts Coldplay dipping into EDM on “Hymn for the Weekend,” while dance diva Hailee Steinfeld and electro duo Grey strip down for the Zedd-assisted “Starving.”