Actors Idris Elba (“Prometheus”) and Naomie Harris (“Skyfall”), along with director Justin Chadwick discuss their new film, “Mandela: Long Walk to Freedom,” based on South African President Nelson Mandela’s autobiography of the same name. Starring Elba and Harris as Nelson and Winnie Mandela, the movie chronicles Mandela’s early life, as well as his anti-apartheid struggle, his imprisonment, and his efforts to rebuild the country’s once segregated society.