Stater Bros. Markets took a big step toward its new corporate headquarters and distribution center Friday, when the chain became the owner of a 160-acre site on the former Norton Air Force Base.The Colton-based chain has had a deal with the Inland Valley Development Agency, the developer of the portions of the former base not being used for aviation, for more than a year. All the conditions of the deal were completed Friday, said Jack Brown, Stater Bros.’ chairman of the board and chief executive officer. A few more permits are needed but construction will start soon, Brown said. “We’re ready to come out of the ground,” Brown said by phone. “Now it’s just going to be a matter of bricks and mortar.” Stater Bros. held a ceremonial groundbreaking in February, but some existing tenants at the site had to be relocated and old warehouses — some dating to the World War II era — torn down, Brown said. Also, IVDA had to ensure the site was environmentally safe. Construction will be completed in phases and take 18 months to complete, Brown said. Stater Bros. headquarters and its main distribution center on Barton Road have been in Colton for more than 45 years. But the chain has distribution facilities and offices in several other Inland cities, and bringing them together under one roof has long been a goal. The project, which has a price estimated at $200 million, will eventually house more than 1,600 employees and generate a payroll estimated at $3 billion over the next 20 years.