Singer Chris Brown’s punishment for assaulting his pop star girlfriend, Rihanna, is expected to become official Wednesday in a Los Angeles courtroom. Rihanna will not attend Brown’s sentencing, where a judge is expected to impose five years of probation and about 1,400 hours in “labor-oriented service.” “Her presence is not required,” Rihanna’s lawyer Donald Etra said. “She will be working out of state.” Rihanna, whose real name is Robyn Rihanna Fenty, appeared briefly in court in June after Brown admitted guilt to a felony assault in a plea deal