Fix typo in js code when checking the origin of a message coming from the

chrome/browser/resources/gaia_auth_host/authenticator.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 An UI component to authenciate to Chrome. The component hosts
  * IdP web pages in a webview. A client who is interested in monitoring
  * authentication events should pass a listener object of type
  * cr.login.GaiaAuthHost.Listener as defined in this file. After initialization,
  * call {@code load} to start the authentication flow.
@@ skipping 230 matching lines @@
     }
   };
 
   /**
    * Invoked when an HTML5 message is received from the webview element.
    * @param {object} e Payload of the received HTML5 message.
    * @private
    */
   Authenticator.prototype.onMessageFromWebview_ = function(e) {
     // The event origin does not have a trailing slash.
-    if (e.origin != this.idpOrigin_.substring(0, this.idpOrigin_ - 1)) {
+    if (e.origin != this.idpOrigin_.substring(0, this.idpOrigin_.length - 1)) {
       return;
     }
 
     var msg = e.data;
     if (msg.method == 'attemptLogin') {
       this.email_ = msg.email;
       this.password_ = msg.password;
       this.chooseWhatToSync_ = msg.chooseWhatToSync;
     }
   };
@@ skipping 42 matching lines @@
 
   Authenticator.AuthFlow = AuthFlow;
   Authenticator.AuthMode = AuthMode;
 
   return {
     // TODO(guohui, xiyuan): Rename GaiaAuthHost to Authenticator once the old
     // iframe-based flow is deprecated.
     GaiaAuthHost: Authenticator
   };
 });