SafariServices iOS 11.0 Beta 2 to Beta 3 API Differences

SFAuthenticationSession.h

Added SFAuthenticationError

Added SFAuthenticationErrorCanceledLogin

Added SFAuthenticationErrorDomain

Added SFAuthenticationCompletionHandler

Added SFAuthenticationSession

Added -[SFAuthenticationSession initWithURL:callbackURLScheme:completionHandler:]

Added -[SFAuthenticationSession start]

Added -[SFAuthenticationSession cancel]