text: /** @license
   * Copyright 2016 Google LLC
   * SPDX-License-Identifier: Apache-2.0
   */
  
  goog.provide('shaka.polyfill.Fullscreen');
  
  goog.require('shaka.polyfill');
  
  
  /**
   * @summary A polyfill to unify fullscreen APIs across browsers.
   * Many browsers have prefixed fullscreen methods on Element and document.
   * See {@link https://mzl.la/2K0xcHo Using fullscreen mode} on MDN for more
   * information.
   */
  shaka.polyfill.Fullscreen = class {
    /**
     * Install the polyfill if needed.
     */
    static install() {
      if (!window.Document) {
        // Avoid errors on very old browsers.
        return;
      }
  
      // eslint-disable-next-line no-restricted-syntax
      let proto = Element.prototype;
      proto.requestFullscreen = proto.requestFullscreen ||
                                proto.mozRequestFullScreen ||
                                proto.msRequestFullscreen ||
                                proto.webkitRequestFullscreen;
  
      // eslint-disable-next-line no-restricted-syntax
      proto = Document.prototype;
      proto.exitFullscreen = proto.exitFullscreen ||
                             proto.mozCancelFullScreen ||
                             proto.msExitFullscreen ||
                             proto.webkitExitFullscreen;
  
      if (!('fullscreenElement' in document)) {
        Object.defineProperty(document, 'fullscreenElement', {
          get: () => {
            return document.mozFullScreenElement ||
                   document.msFullscreenElement ||
                   document.webkitFullscreenElement;
          },
        });
        Object.defineProperty(document, 'fullscreenEnabled', {
          get: () => {
            return document.mozFullScreenEnabled ||
                   document.msFullscreenEnabled ||
                   document.webkitSupportsFullscreen ||
                   document.webkitFullscreenEnabled;
          },
        });
      }
  
      const proxy = shaka.polyfill.Fullscreen.proxyEvent_;
      document.addEventListener('webkitfullscreenchange', proxy);
      document.addEventListener('webkitfullscreenerror', proxy);
      document.addEventListener('mozfullscreenchange', proxy);
      document.addEventListener('mozfullscreenerror', proxy);
      document.addEventListener('MSFullscreenChange', proxy);
      document.addEventListener('MSFullscreenError', proxy);
    }
  
    /**
     * Proxy fullscreen events after changing their name.
     * @param {!Event} event
     * @private
     */
    static proxyEvent_(event) {
      const eventType = event.type.replace(/^(webkit|moz|MS)/, '').toLowerCase();
  
      let newEvent;
      // IE 11 does not have an Event constructor
      if (typeof(Event) === 'function') {
        newEvent = new Event(eventType, /** @type {EventInit} */(event));
      } else {
        newEvent = document.createEvent('Event');
        newEvent.initEvent(eventType, event.bubbles, event.cancelable);
      }
  
      event.target.dispatchEvent(newEvent);
    }
  };
  
  
  shaka.polyfill.register(shaka.polyfill.Fullscreen.install);
  