Chinese tech giant Tencent is increasing its minority stake in Ubisoft in a deal with the company’s founding family that values France’s biggest video game maker at more than €10-billion amid a wave of buyouts in the industry. The deal underscores the appetite of deep-pocketed Chinese gaming giants for foreign studios and comes just a week after the acquisition by NetEase of unlisted French video games maker Quantic Dream. It also caps a difficult four-year period at Ubisoft, home to the “Assassin’s Creed” and “Tom Clancy’s” video game franchises, marked by a succession of delays of new video games and...