Google will notify you both in Chrome via pop-up and through email when any of your saved passwords are compromised. Change them as quickly as possible to prevent personal information from being leaked. It’s worth noting that you have to change passwords on each individual site where they were compromised. Passwords are most easily compromised when the same one is used across multiple sites. Take the time to create unique passwords for each account you create and let Google save them for you so you don’t have to worry about remembering.