Index: Src/GoogleApis.Auth/OAuth2/IAuthorizationCodeInstalledApp.cs
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+/*
+Copyright 2013 Google Inc
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace Google.Apis.Auth.OAuth2
+{
+    /// <summary>
+    /// Authorization code flow for an installed application that persists end-user credentials.
+    /// </summary>
+    public interface IAuthorizationCodeInstalledApp
+    {
+        /// <summary>Gets the authorization code flow.</summary>
+        IAuthorizationCodeFlow Flow { get; }
+
+        /// <summary>Gets the code receiver.</summary>
+        ICodeReceiver CodeReceiver { get; }
+
+        /// <summary>Authorizes the installed application to access user's protected data.</summary>
+        /// <param name="userId">User identifier</param>
+        /// <param name="taskCancellationToken">Cancellation token to cancel an operation</param>
+        /// <returns>The user's credential</returns>
+        Task<Credential> Authorize(string userId, CancellationToken taskCancellationToken);
+    }
+}