While trying to enable webview sign-in by default, I found a bunch of issues

chrome/browser/resources/inline_login/inline_login.js

 // Copyright 2013 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 Inline login UI.
  */
 
 cr.define('inline.login', function() {
   'use strict';
 
   /**
    * The auth extension host instance.
    * @type {cr.login.GaiaAuthHost}
    */
   var authExtHost;
 
   /**
    * Whether the auth ready event has been fired, for testing purpose.
    */
   var authReadyFired;
 
-  /**
-   * A listener class for authentication events from GaiaAuthHost.
-   * @constructor
-   * @implements {cr.login.GaiaAuthHost.Listener}
-   */
-  function GaiaAuthHostListener() {}
+  function onResize(e) {
+    chrome.send('switchToFullTab', [e.detail]);
+  }
 
-  /** @override */
-  GaiaAuthHostListener.prototype.onSuccess = function(credentials) {
-    onAuthCompleted(credentials);
-  };
-
-  /** @override */
-  GaiaAuthHostListener.prototype.onReady = function(e) {
-    onAuthReady();
-  };
-
-  /** @override */
-  GaiaAuthHostListener.prototype.onResize = function(url) {
-    chrome.send('switchToFullTab', [url]);
-  };
-
-  /** @override */
-  GaiaAuthHostListener.prototype.onNewWindow = function(e) {
-    window.open(e.targetUrl, '_blank');
-    e.window.discard();
-  };
-
-  /**
-   * Handler of auth host 'ready' event.
-   */
-  function onAuthReady() {
+  function onAuthReady(e) {
     $('contents').classList.toggle('loading', false);
     authReadyFired = true;
   }
 
-  /**
-   * Handler of auth host 'completed' event.
-   * @param {!Object} credentials Credentials of the completed authentication.
-   */
-  function onAuthCompleted(credentials) {
+  function onNewWindow(e) {
+    window.open(e.detail.targetUrl, '_blank');
+    e.window.discard();
+  }
+
+  function onAuthCompleted(e) {
+    completeLogin(e.detail);
+  }
+
+  function completeLogin(credentials) {
     chrome.send('completeLogin', [credentials]);
     $('contents').classList.toggle('loading', true);
   }
 
   /**
    * Initialize the UI.
    */
   function initialize() {
-    authExtHost = new cr.login.GaiaAuthHost(
-        'signin-frame', new GaiaAuthHostListener());
+    authExtHost = new cr.login.GaiaAuthHost('signin-frame');
     authExtHost.addEventListener('ready', onAuthReady);
-
+    authExtHost.addEventListener('newWindow', onNewWindow);
+    authExtHost.addEventListener('resize', onResize);
+    authExtHost.addEventListener('authCompleted', onAuthCompleted);
     chrome.send('initialize');
   }
 
   /**
    * Loads auth extension.
    * @param {Object} data Parameters for auth extension.
    */
   function loadAuthExtension(data) {
-    authExtHost.load(data.authMode, data, onAuthCompleted);
+    // TODO(rogerta): in when using webview, the |completeLogin| argument
+    // is ignored.  See addEventListener() call above.
+    authExtHost.load(data.authMode, data, completeLogin);
     $('contents').classList.toggle('loading',
         data.authMode != cr.login.GaiaAuthHost.AuthMode.DESKTOP ||
         data.constrained == '1');
   }
 
   /**
    * Closes the inline login dialog.
    */
   function closeDialog() {
     chrome.send('dialogClose', ['']);
@@ skipping 26 matching lines @@
     getAuthExtHost: getAuthExtHost,
     isAuthReady: isAuthReady,
     initialize: initialize,
     loadAuthExtension: loadAuthExtension,
     closeDialog: closeDialog,
     handleOAuth2TokenFailure: handleOAuth2TokenFailure
   };
 });
 
 document.addEventListener('DOMContentLoaded', inline.login.initialize);