I have a website that allows sign-ins via OAuth, where a user may use a 3rd party iPhone app to log in. Later, if the same user on the same device downloads the official 1st party app through the App Store, I'd like to automatically log them in on first launch, without any login prompt (since they've already logged in through a 3rd party app).
From research, it seems this was possible in iOS 9 and 10, using a hidden SFSafariViewController. However iOS 11 disable session sharing between Safari instances and instead we should use SFAuthenticationSession. It's not clear if automatic login on the downloaded 1st party app is possible with SFAuthenticationSession. Any solutions here?