Allow the background page to get an OAuth token for apps v1.

remoting/webapp/crd/js/it2me_helpee_channel.js

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 /**
  * @fileoverview
  *
  * It2MeHelpeeChannel relays messages between the Hangouts web page (Hangouts)
  * and the It2Me Native Messaging Host (It2MeHost) for the helpee (the Hangouts
  * participant who is receiving remoting assistance).
@@ skipping 356 matching lines @@
   return new Promise(function(resolve, reject) {
     if (host.initialized()) {
       resolve();
     } else {
       host.initialize(resolve, reject);
     }
   });
 };
 
 /**
- * TODO(kelvinp): The existing implementation only works in the v2 app
- * We need to implement token fetching for the v1 app using remoting.OAuth2
- * before launch (crbug.com/405130).
- *
  * @return {Promise} Promise that resolves with the OAuth token as the value.
  */
 remoting.It2MeHelpeeChannel.prototype.fetchOAuthToken_ = function() {
-  if (!base.isAppsV2()) {
-    throw new Error('fetchOAuthToken_ is not implemented in the v1 app.');
+  if (base.isAppsV2()) {
+    /**
+     * @param {function(*=):void} resolve
+     */
+    return new Promise(function(resolve){
+      // TODO(jamiewalch): Make this work with {interactive: true} as well.
+      chrome.identity.getAuthToken({ 'interactive': false }, resolve);
+    });
+  } else {
+    /**
+     * @param {function(*=):void} resolve
+     */
+    return new Promise(function(resolve) {
+      /** @type {remoting.OAuth2} */
+      var oauth2 = new remoting.OAuth2();
+      var onAuthenticated = function() {
+        oauth2.callWithToken(
+            resolve,
+            function() { throw new Error('Authentication failed.'); });
+      };
+      /** @param {remoting.Error} error */
+      var onError = function(error) {
+        if (error != remoting.Error.NOT_AUTHENTICATED) {
+          throw new Error('Unexpected error fetch auth token: ' + error);
+        }
+        oauth2.doAuthRedirect(onAuthenticated);
+      };
+      oauth2.callWithToken(resolve, onError);
+    });
   }
-
-  /**
-   * @param {function(*=):void} resolve
-   */
-  return new Promise(function(resolve){
-    chrome.identity.getAuthToken({ 'interactive': false }, resolve);
-  });
 };
 
 /**
  * Connects to the It2Me Native Messaging Host and retrieves the access code
  * in the |onHostStateChanged_| callback.
  *
  * @param {string} email
  * @param {string} accessToken
  * @private
  */
@@ skipping 68 matching lines @@
 
   console.error('Error responding to message method:' +
                 (incomingMessage ? incomingMessage.method : 'null') +
                 ' error:' + error);
   this.hangoutPort_.postMessage({
     method: remoting.It2MeHelpeeChannel.HangoutMessageTypes.ERROR,
     message: error,
     request: incomingMessage
   });
 };