As we have all learned, the past inevitably bumps up against the present. Sometimes it’s a headache, sometimes it’s an opportunity, and sometimes it’s a bit of both. Such is the case of the long-overdue reunion between Kenyatta (the riveting Russell Hornsby), a former Black revolutionary, and his estranged daughter Nina (the magnificent, heartbreaking Moses Ingram), a small-time hustler, in Dominique Morriseau’s bracing 2013 drama “Sunset Baby,” now being given a superb revival at the Signature Theatre Company under Steve H. Broadnax III’s sure-handed direction.