Chris Brown’s legal troubles got more serious Tuesday when a Los Angeles prosecutor charged him in a minor traffic crash. Brown already faces a charge that he violated his probation in connection with his felony assault conviction in the beating of his girlfriend Rihanna. Brown, 24, allegedly was driving a car that rear-ended another car in Los Angeles in May. The Los Angeles city attorney filed charges of hit-and-run driving and driving without a license, according to spokesman Frank Mateljan.