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)

Number.isInteger(pageNumber) && this._pages[pageNumber - 1];
    if (!pageView) {
      console.error(
        `${this._name}.scrollPageIntoView: ` +
          `"${pageNumber}" is not a valid pageNumber parameter.`
      );
      return;
    }
    if (this.isInPresentationMode || !destArray) {
      this._setCurrentPageNumber(pageNumber,  true);
      return;
    }
    let x = 0,
      y = 0;
    let width = 0,
      height = 0,
      widthScale,
      heightScale;
    const changeOrientation = pageView.rotation % 180 !== 0;
    const pageWidth =
      (changeOrientation ? pageView.height : pageView.width) /
      pageView.scale /
      CSS_UNITS;
    const pageHeight =
      (changeOrientation ? pageView.width : pageView.height) /
      pageView.scale /
      CSS_UNITS;
    let scale = 0;
    switch (destArray[1].name) {
      case "XYZ":