DETROIT—General Motors Co. Chief Executive Mary Barra told investors on Wednesday that the automaker plans to double revenue by 2030, expanding profits from combustion vehicles as it rolls out new electric vehicles and new digitally powered services in a bid to catch up with Tesla Inc. If GM succeeds, its annual revenue by 2030 would be about $244 billion, and the automaker would be the leader in electric vehicle sales in the United States. At GM’s current pre-tax profit margin of 12 percent, that would imply annual pre-tax profits of as much as $29 billion. Sources told Reuters previously that GM would report impressive revenue growth and margin expansion. Barra’s ambitious financial targets for 2030 are the latest push in her campaign to convince investors that General Motors, not Tesla, can be the leader in both technology development and profitability as the auto industry navigates the most profound technology revolution …