There's a major security flaw with auto-fill when it comes to passwords. Sure, it's hidden on screen, but you only have to change the password box's type, so it isn't "type='password'" and it is revealed. This only takes a matter of seconds.
Chrome should remove the password if there is any attempt to change that form object.
This flaw has been there for years, it's actually handy if I'm not sure what the password is.