I am planning to use Google Identity Toolkit and will integrate only with Google Provider (no other providers and no chance in the future too).
Whatever example I have seen, flow is showing "Email First" option.After providing email based on domain, it takes to identity provider site.
Scenario is, if user is not logged in, user is required to enter his email address twice, first on "Email First" page, then on Google Account Page.
As I have, only Google as provider, question is how can I directly redirect user to Google Account, once he clicks Sign-In button, instead of showing him "Email First" page?
Edited
Now I have little change in the flow, the web site I am working with has been integrated with different companies active directory, so once user enter his email address, based on email domain user would be redirected to required company portal for user verification.
Now web site is planning to allow Google accounts and when user enter email address with Google domain, use should be redirected to Google Account Page. Web site owner, does not want to see "Email First" or "Provider First" screen as this is bad user experiences.