Add support for linking to external users in entity search

data/users/__init__.py

@@ -139,6 +139,31 @@ class UserAuthentication(object):
 
     return data.get('password', encrypted)
 
+  @property
+  def federated_service(self):
+    """ Returns the name of the federated service for the auth system. If none, should return None.
+    """
+    return self.state.federated_service
+
+  def query_users(self, query, limit=20):
+    """ Performs a lookup against the user system for the specified query. The returned tuple
+        will be of the form (results, federated_login_id, err_msg). If the method is unsupported,
+        the results portion of the tuple will be None instead of empty list.
+
+        Note that this method can and will return results for users not yet found within the
+        database; it is the responsibility of the caller to call link_user if they need the
+        database row for the user system record.
+
+        Results will be in the form of objects's with username and email fields.
+    """
+    return self.state.query_users(query, limit)
+
+  def link_user(self, username_or_email):
+    """ Returns a tuple containing the database user record linked to the given username/email
+        and any error that occurred when trying to link the user.
+    """
+    return self.state.link_user(username_or_email)
+
   def confirm_existing_user(self, username, password):
     """ Verifies that the given password matches to the given DB username. Unlike
         verify_credentials, this call first translates the DB user via the FederatedLogin table