Five years after it shook up the Web with its unexpected debut, Chrome gambles again as it takes the Web offline with its new “packaged apps.” Looking at its history, Google’s a betting company. On September 4, 1998, the company bet that the world would want a better search engine. On September 2, 2008, the company bet thatpeople would want a better browser. And on Thursday, the company unveiled a new kind of Chrome App that bets that people want to use Web apps, sans browser.