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)

if (!this.pdfDocument) {
      return;
    }
    let page = val | 0; 
    if (this._pageLabels) {
      const i = this._pageLabels.indexOf(val);
      if (i >= 0) {
        page = i + 1;
      }
    }
    
    if (!this._setCurrentPageNumber(page,  true)) {
      console.error(
        `${this._name}.currentPageLabel: "${val}" is not a valid page.`
      );
    }
  }
  /**
   * @type {number}
   */
  get currentScale() {
    return this._currentScale !== UNKNOWN_SCALE
      ? this._currentScale
      : DEFAULT_SCALE;
  }
  /**
   * @param {number} val - Scale of the pages in percents.
   */
  set currentScale(val) {