The 17-time Oscar nominee tells IndieWire about her latest song, "Dear Me," and how she approached writing for a movie in which she was the subject. There’s a funny motif in Bess Kargman’s documentary “Diane Warren: Relentless” when it comes to its subject’s enthusiasm about her own work: seemingly every time Diane Warren — one of the most successful songwriters in the history of pop music, with chart-topping hits by everyone from Aerosmith and Chicago to Brandy, Celine Dion, and Toni Braxton