Login Through Facebook App WebView Hanging With Gray Screen

[dcrockwell]

To Reproduce:

1. setup a simple page using oauth.io and facebook as the login provider
2. post the url to your simple page onto a facebook page post
3. use the Facebook iOS mobile app to go to that page and click the link
4. When the WebView pops up, login as you normally would
5. notice that after submitting login credentials, you are stuck on a gray screen
6. If you copy the url into safari, oauth.io returns the following error (which may be unrelated since we are changing browsers during this step):

Cannot read property 'state' of undefined
code: InternalError
message: Cannot read property 'state' of undefined

[dcrockwell]

When I completely removed oauth.io and reverted back to the original FB.login function provided by Facebook's SDK, the error was not present. It seems to be related directly to Oauth.io and not Facebook.