Sony capped off its CinemaCon 2018 presentation with a surprise: Quentin Tarantino and Leonardo DiCaprio took the stage at the Colosseum at Caesar’s Palace to chat about their upcoming feature Once Upon a Time in Hollywood which they haven’t shot a frame of yet. Tarantino said that the pic takes place in LA in 1969 during the counterculture explosion and “block by block” this summer he’ll take LA back to that era. “It takes place during the 1969 Hollywood era at the…