Gov. Gavin Newsom, in the Central Valley on Wednesday for a firsthand look at one of the largest oil spills in California history, vowed to go beyond the state’s already aggressive efforts to curtail the use of fossil fuels and seek a long-term strategy to reduce oil production. Newsom also signaled a sharp break with that past by criticizing existing oversight of the oil industry as too permissive. He promised to begin by retooling the state’s top oil regulatory agency, state Division of Oil, Gas and Geothermal Resources.