Bringing an end to its manufacturing history in California, Vans Inc. said it will close its shoe factory in Vista and fire 300 workers. The closure is the latest step in a three-year restructuring in which the maker of trendy footwear has emphasized marketing over manufacturing. Vans, which was founded in Orange in 1966, closed its manufacturing plant in that city in 1995, and laid off about 1,000 workers. The following year it moved its headquarters to Santa Fe Springs. The company said it plans to focus on marketing its products, and will contract out production to other manufacturers. The Vista plant will close Aug. 6, the company said, after which production will move to Mexico and Spain. The move will reduce its costs and boost profit, the company said. Vans' stock closed at $10.19 a share, down 6 cents, in Nasdaq trading.