LaChanze has spent most of her life on stage, appearing in such shows as “Once on This Island,” “Ragtime,” “Summer,” and “The Color Purple,” for which she won a Tony Award. But throughout her career she did not see much diversity backstage. And so, after 40 years as a performer, LaChanze took on a new role as a Broadway producer – and won two more Tonys, for best musical (“Kimberly Akimbo”) and best revival of a play (“Top Dog/Underdog”). She talks with correspondent David Pogue about the strides for inclusivity made by her advocacy organization, Black Theater United.