An antitrust class-action lawsuit in the U.S. has been filed against Google Inc., claiming the search engine illegally monopolized and stagnated the American market for Internet and mobile search. The lawsuit, filed by the law firm Hagens Berman in the U.S. District Court for the Northern District of California, said Google’s monopoly of these markets stems from the company’s purchase of the Android mobile operating system, which it used to expand its dominance by pre-loading its own suite of applications onto the devices through secret mobile-application distribution agreements,...