When you save your password in Chrome, they are stored on your local machine and are decrypted once your OS user is logged in. This is why you can view the passwords in plain text although, the main reason is because in order to use auto-fill, Chrome needs to enter the plain text password into the HTML form.

The passwords themselves however are encrypted, and the only way to get them back to plain text is through the decryption key – which is your Google password/secondary key. When you sign into Chrome (and sync to the Google servers) your encrypted password is transmitted along with the settings, bookmarks etc. As a result, Google only has the information stored in an encrypted state and do not have the key to decrypt it.

The only way your passwords are not safe is if, your machine becomes compromised.