The 2-Legged OAuth Authentication with Impersonation provider. 2-Legged OAuth Authentication with Impersonation
authentication can be used to access user-specific information without involving user-interaction (such as the
dance process in standard OAuth). The protocol is based on the standard 2-Legged OAuth
http://oauth.googlecode.com/svn/spec/ext/consumer_request/1.0/drafts/1/spec.html but with a small variation
inspired by how Google implemented the protocol https://developers.google.com/google-apps/gmail/oauth_protocol.
Since the impersonation mechanism can be used to obtain escalated privileges on the remote application, consider
using this authentication mode only if the caller application can be fully trusted.
Pass this type to the
ReadOnlyApplicationLink.createAuthenticatedRequestFactory(Class)
method to obtain a
RequestFactory instance
that uses 2 Legged OAuth with Impersonation authentication for authentication.