Support signing in with an IdP using a redirection

[embesozzi]

It will be great for the user experience to support login as a redirection to the IdP, as this is the standard practice in identity federation. Currently, it supports the popup experience, which is not ideal in some scenarios.

[panva]

I believe same wish goes as an alternative to the popup window experience in the continuation API. A popup limits the real estate for the IdP to work with, unless blocking the tab (much like alert is) can be clicked away and "lost" to the user, <insert more popup-related issues that we have years of historical evidence for here>

[npm1]

Do you mean redirecting to the IdP page after the user has selected an account via FedCM? Isn't this something the IdP can do with sufficient control over the RP page?