extensions/renderer/resources/guest_view/guest_view_deny.js

   1 // Copyright 2015 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 // This module implements the registration of guestview elements when
   6 // permissions are not available. These elements exist only to provide a useful
   7 // error message when developers attempt to use them.
   8
   9 var DocumentNatives = requireNative('document_natives');
  10 var GuestViewContainer = require('guestViewContainer').GuestViewContainer;
  11
  12 var ERROR_MESSAGE = 'You do not have permission to use the %1 element.' +
  13     ' Be sure to declare the "%1" permission in your manifest file.';
  14
  15 // A list of view types that will have custom elements registered if they are
  16 // not already registered by the time this module is loaded.
  17 var VIEW_TYPES = [
  18   'AppView',
  19   'ExtensionOptions',
  20   'ExtensionView',
  21   'WebView'
  22 ];
  23
  24 // Registers a GuestView custom element.
  25 function registerGuestViewElement(viewType) {
  26   var proto = Object.create(HTMLElement.prototype);
  27
  28   proto.createdCallback = function() {
  29     window.console.error(ERROR_MESSAGE.replace(/%1/g, viewType.toLowerCase()));
  30   };
  31
  32   window[viewType] = DocumentNatives.RegisterElement(viewType.toLowerCase(),
  33                                                      {prototype: proto});
  34
  35   // Delete the callbacks so developers cannot call them and produce unexpected
  36   // behavior.
  37   delete proto.createdCallback;
  38   delete proto.attachedCallback;
  39   delete proto.detachedCallback;
  40   delete proto.attributeChangedCallback;
  41 }
  42
  43 var useCapture = true;
  44 window.addEventListener('readystatechange', function listener(event) {
  45   if (document.readyState == 'loading')
  46     return;
  47
  48   for (var i = 0; i != VIEW_TYPES.length; ++i) {
  49     // Register the error-providing custom element only for those view types
  50     // that have not already been registered. Since this module is always loaded
  51     // last, all the view types that are available (i.e. have the proper
  52     // permissions) will have already been registered on |window|.
  53     if (!window[VIEW_TYPES[i]])
  54       registerGuestViewElement(VIEW_TYPES[i]);
  55   }
  56
  57   window.removeEventListener(event.type, listener, useCapture);
  58 }, useCapture);