General Motors Co. said Friday it will invest $300 million to build a new electric car domestically rather than outside the country, a decision that comes as President Trump has blasted the Detroit auto maker for its plans to close four U.S. factories. The planned investment in an existing Michigan plant, GM said, is part of a broader commitment to spend $1.8 billion at its U.S. manufacturing operations, adding 700 jobs in several states over the next three years. …