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)

const scrollMode = this._scrollMode,
      viewer = this.viewer;
    viewer.classList.toggle(
      "scrollHorizontal",
      scrollMode === ScrollMode.HORIZONTAL
    );
    viewer.classList.toggle("scrollWrapped", scrollMode === ScrollMode.WRAPPED);
    if (!this.pdfDocument || !pageNumber) {
      return;
    }
    
    
    
    if (this._currentScaleValue && isNaN(this._currentScaleValue)) {
      this._setScale(this._currentScaleValue, true);
    }
    this._setCurrentPageNumber(pageNumber,  true);
    this.update();
  }
  /**
   * @type {number} One of the values in {SpreadMode}.
   */
  get spreadMode() {