After decades of global expansion and consolidation in the tech sector, antitrust is now a headline issue for the industry across the world. What has been a slow and sputtering series of disparate actions over the past decade has coalesced in just the past few weeks into a rapid and comprehensive series of actions against the industry, with the United States being a notable laggard worldwide. Nowhere are these actions more prominent than in China, where the competition authorities have — after many years of a reasonably laissez-faire policy to…