The root origin was added to the FormData and FormStructure objects in this CL: https://chromium-review.googlesource.com/c/chromium/src/+/770654

The reason was that for logging, we want the top level frame url, even if the form is in an iframe with a different origin.

Investigate whether this is useful for passwords in objects such as PasswordForm and PasswordFillFormData.

Also check whether it should be added in the operator== of FormData and FormStructure.