Issue 463: Provide a signout\logout method

Src/GoogleApis.Auth.WinRT/OAuth2/AuthorizationCodeWinRTInstalledApp.cs

 /*
 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
@@ skipping 13 matching lines @@
 {
 /// <summary>
 /// OAuth 2.0 authorization code flow for a Windows 8 installed applications
that persists end-user credentials.
 /// <remarks>
 /// This installed app class uses an internal <seealso cref="AuthorizationCo
deInstalledApp"/> with a
 /// <seealso cref="Google.Apis.Auth.OAuth2.AuthorizationCodeBroker"/> for re
trieving the authorization code.·
 /// </remarks>
 /// </summary>
 public sealed class AuthorizationCodeWinRTInstalledApp : IAuthorizationCodeI
nstalledApp
 {
- private IAuthorizationCodeInstalledApp innerInstallApp;
+ private readonly IAuthorizationCodeInstalledApp innerInstallApp;
 
- private readonly AuthorizationCodeFlow.Initializer authorizationCodeFlow
 Initializer;
-
- /// <summary>Constructs a new authorization code installed application f
 or Windows Store.</summary>
- /// <param name="authorizationCodeFlowInitializer">A authorization code 
 flow initializer</param>
+ /// <summary>
+ /// Constructs a new authorization code for Windows Store application ta
 rgeting an installed application flow.
+ /// </summary>
+ /// <param name="authorizationCodeFlowInitializer">An authorization code
  flow initializer.</param>
 public AuthorizationCodeWinRTInstalledApp(AuthorizationCodeFlow.Initiali
zer authorizationCodeFlowInitializer)
 {
- this.authorizationCodeFlowInitializer = authorizationCodeFlowInitial
 izer;
+ innerInstallApp = new AuthorizationCodeInstalledApp(
+ new AuthorizationCodeFlow(authorizationCodeFlowInitializer), new
  AuthorizationCodeBroker());
+ }
+
+ /// <summary>
+ /// Constructs a new authorization code for Windows Store application ta
 rgeting an installed application flow.
+ /// </summary>
+ /// <param name="flow">An authorization code flow.</param>
+ public AuthorizationCodeWinRTInstalledApp(IAuthorizationCodeFlow flow)
+ {
+ innerInstallApp = new AuthorizationCodeInstalledApp(flow, new Author
 izationCodeBroker());
 }
 
 #region IAuthorizationCodeInstalledApp Members
 
 public IAuthorizationCodeFlow Flow
 {
 get { return innerInstallApp.Flow; }
 }
 
 public ICodeReceiver CodeReceiver
 {
 get { return innerInstallApp.CodeReceiver; }
 }
 
 public async Task<UserCredential> AuthorizeAsync(string userId, Cancella
tionToken taskCancellationToken)
 {
-if (innerInstallApp == null)
-{
-innerInstallApp = new AuthorizationCodeInstalledApp(
-new AuthorizationCodeFlow(authorizationCodeFlowInitializer),
new AuthorizationCodeBroker());
-}
-
 return await innerInstallApp.AuthorizeAsync(userId, taskCancellation
Token).ConfigureAwait(false);
 }
 
 #endregion
 }
 }