You have posted a link to a Chromium doc related to using SAML within a Chromebook without directly stating you are using an F5 APM as a SAML IdP and also assume we all have the time to read up on 'Advanced Integration for SAML SSO on Chrome Devices'
If you don't make it clear you will not likely get the help you are after.
However, I think want you need to do is create a customised logon page within the APM and add in the JavaScript, linked to in the documentation, and write a bit of additional javascript around the login form calling the three methods:
google.principal.initialize(callback)
- Once at the start of the authentication flow.google.principal.add(details, callback)
- When the user has finished entering his/her credentialsgoogle.principal.complete(details, callback)
- When user’s credentials have been verified by the SAML IdP and the user is authenticated.
Basically this is a locally executed process via javascript but needs to be provided by the logon page/form without interfering with the F5 APM authentication process its self.
That is until you get to the
complete
method as the F5 APM needs to pass the
RelayState
and
SAMLResponse
to a Google URL.
Finally though I do know Javascript I only really write back-end stuff and never front-end web stuff so not sure on the best approach for this, need someone with some front-end javascript experience I think.