Traditionally applications have asked the user if they're sure they want to quit. That's a no-no these days, but it's still a reasonable choice in situations where the cost of quitting might be high (there's unsaved content, or the app takes a long time to start, or it's impossible to persist the current state of the application).
For some time, the Chrome team refused to implement a 'Sure you want to quit?' popup due to a general anti-popups consensus. They also refused to implement a checkbox to enable that behavior due to a general anti-configuration consensus. They've since relented on the latter.
