Index: Src/GoogleApis.Auth/OAuth2/TokenRequestExtenstions.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.Net.Http;
+using System.Threading;
+using System.Threading.Tasks;
+
+using Google.Apis.Auth.OAuth2.Requests;
+using Google.Apis.Auth.OAuth2.Responses;
+using Google.Apis.Json;
+using Google.Apis.Requests.Parameters;
+using Google.Apis.Util;
+
+namespace Google.Apis.Auth.OAuth2
+{
+    /// <summary>
+    /// Extension methods to <seealso cref="Google.Apis.Auth.OAuth2.Requests.ToeknRequest"/>.
+    /// </summary>
+    internal static class TokenRequestExtenstions
+    {
+        /// <summary>
+        /// Executes the token request in order to receive a 
+        /// <seealso cref="Google.Apis.Auth.OAuth2.Responses.TokenResponse"/>. In case the token server returns an 
+        /// error, a <seealso cref="Google.Apis.Auth.OAuth2.Responses.TokenResponseException"/> is thrown.
+        /// </summary>
+        /// <param name="request">The token request.</param>
+        /// <param name="httpClient">The HTTP client used to create an HTTP request.</param>
+        /// <param name="tokenServerUrl">The token server URL.</param>
+        /// <param name="taskCancellationToken">Cancellation token to cancel operation.</param>
+        /// <param name="clock">The clock which is used to set the <seealso cref="Clock.Issued"/> property.</param>
+        /// <returns>Token response with the new access token.</returns>
+        public static async Task<TokenResponse> Execute(this TokenRequest request, HttpClient httpClient,
+            string tokenServerUrl, CancellationToken taskCancellationToken, IClock clock)
+        {
+            var httpRequest = new HttpRequestMessage(HttpMethod.Post, tokenServerUrl);
+            httpRequest.Content = ParameterUtils.CreateFormUrlEncodedContent(request);
+
+            var response = await httpClient.SendAsync(httpRequest, taskCancellationToken).ConfigureAwait(false);
+            var content = await response.Content.ReadAsStringAsync().ConfigureAwait(false);
+
+            if (!response.IsSuccessStatusCode)
+            {
+                var error = NewtonsoftJsonSerializer.Instance.Deserialize<TokenErrorResponse>(content);
+                throw new TokenResponseException(error);
+            }
+
+            // Gets the token and sets its issued time.
+            var newToken = NewtonsoftJsonSerializer.Instance.Deserialize<TokenResponse>(content);
+            newToken.Issued = clock.Now;
+            return newToken;
+        }
+    }
+}