A man and a woman are scheduled to be arraigned today on charges that they stole baby formula from a Pleasanton grocery store and then led police on a high-speed chase. Pleasanton police said officers who were patrolling the parking lot at the Safeway store at 6790 Bernal Ave. early Wednesday spotted a man later identified as 21-year-old Demarko Luke, of Oakland, running out of the store carrying two baskets of Enfamil baby formula.