To my understanding, chrome's incognito mode means everything you did within incognito will not be saved and applied to regular mode. But everything you did within regular mode will be applied to incognito. This works for localstorage and passwords. (Not sure about cookies, since my login session doesn't preserve in incognito, I guess cookie is not shared)
Are you sure it keeps localstorage? I was under the impression that passwords from normal mode were shared because that's a "meta" feature of the browser rather than part of the API web pages use, but localstorage and cookies weren't.
Well, I just checked and it looks like localStorage is not shared. But I recall it was shared when I checked sometime last year, maybe a bug back then.
