I am quite confident that the default behaviour when you install chrome is that you are not signed in. It definitely doesn't share any history when you're not signed in. It wouldn't make a lot of sense to have a login box otherwise ;)

I also feel that the message you get when you decide whether or not to sign in to chrome makes the purpose of this feature quite clear: "Sign in to get your bookmarks, history and settings on all your devices." Here's the detailed page it links to: https://www.google.com/intl/en_uk/chrome/browser/signin.html

I'm not sure what behaviour you were expecting, can you clarify?