His son, Tony Nicholas, tells the Los Angeles Times ( http://lat.ms/15L6WFQ) that Branton died on April 19 in Los Angeles.
The Times says Branton also helped singer Nat King Cole integrate a wealthy Los Angeles neighborhood, won police misconduct cases and defended Communists in the McCarthy era.
He was co-lead counsel at the trial of Davis, who faced a potential death penalty because a gun registered in her name was linked to the murder of a Marin County judge.
Davis, who was black, won acquittal from an all-white jury.
Davis tells the Times that Branton's brilliant closing argument had a profound impact on the jury.
Information from: Los Angeles Times, http://www.latimes.com