I was wondering if WebGL is considered stable enough to be enabled by default. It makes some PDFs render much faster and it has been off by default for a while now, so we have had quite some time to test it.

If we decide to enable WebGL by default, we should not forget to update https://github.com/mozilla/pdf.js/blob/master/extensions/chromium/preferences_schema.json#L39 as well.

/cc @yurydelendik 
/cc @Snuffleupagus (because IIRC you were testing WebGL too)

return this._pageIndex + 1;
  }
  /**
   * @type {number} The number of degrees the page is rotated clockwise.
   */
  get rotate() {
    return this._pageInfo.rotate;
  }
  /**
   * @type {Object} The reference that points to this page. It has `num` and
   *   `gen` properties.
   */
  get ref() {
    return this._pageInfo.ref;
  }
  /**
   * @type {number} The default size of units in 1/72nds of an inch.
   */
  get userUnit() {
    return this._pageInfo.userUnit;
  }
  /**
   * @type {Array<number>} An array of the visible portion of the PDF page in
   *   user space units [x1, y1, x2, y2].
   */
  get view() {