chrome/browser/resources/identity_scope_approval_dialog/background.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.

/**
 * Displays a webview based authorization dialog.
 * @param {string} key A unique identifier that the caller can use to locate
 *     the dialog window.
 * @param {string} url A URL that will be loaded in the webview.
 * @param {string} mode 'interactive' or 'silent'. The window will be displayed
 *     if the mode is 'interactive'.
 */
function showAuthDialog(key, url, mode) {
  var options = {
    frame: 'none',
    id: key,
    minWidth: 1024,
    minHeight: 768,
    hidden: true
  };
  chrome.app.window.create('scope_approval_dialog.html',
                           options,
                           function(win) {
    win.contentWindow.addEventListener('load', function(event) {
      var windowParam;
      if (mode == 'interactive')
        windowParam = win;
      win.contentWindow.loadAuthUrlAndShowWindow(url, windowParam);
    });
  });
}

chrome.identityPrivate.onWebFlowRequest.addListener(showAuthDialog);