Configure claims-based authentication for a form-based web application in SharePoint 2013 through ADFS 2.0?

My customer, Fabrikam, is half-owned by Contoso and has an AD of its own. There are trust setup between Contoso AD and Fabrikam AD. The users of Contoso access the web application using form-based authentication and access its intranet in a single sign-on fashion and working well. Fabrikam users should use single-sign on through Claim based authentication.

Now I know it’s possible to implement form-based authentication on a claims web application following the article Configure forms-based authentication for a claims-based web application in SharePoint 2013. However, is it possible to do it the other way around?

How do I configure claims-based authentication for a form-based web application in SharePoint 2013?

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^{General disclaimer: Fabrikam and Contoso are not the real names of my customer.}