OAKLAND — Los Angeles County will reinstate indoor mask requirements in public spaces for all this weekend, regardless of vaccination status, amid an alarming rise in Covid-19 cases driven by the Delta variant. Thursday’s announcement by the nation's largest county sent a chill through the state just one month into California's long-awaited reopening. And it could prompt other local health officials to follow suit, complicating the post-pandemic recovery narrative of Gov. Gavin Newsom as he faces a September recall election. Los Angeles County just over two weeks ago recommended that people wear masks indoors, a step that Sacramento County health officials also took on Thursday and that Yolo County initiated a day earlier.