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)

break;
      case 115: 
        PDFViewerApplication.pdfSidebar.toggle();
        break;
    }
    if (
      turnPage !== 0 &&
      (!turnOnlyIfPageFit || pdfViewer.currentScaleValue === "page-fit")
    ) {
      if (turnPage > 0) {
        pdfViewer.nextPage();
      } else {
        pdfViewer.previousPage();
      }
      handled = true;
    }
  }
  
  if (cmd === 4) {
    switch (evt.keyCode) {
      case 13: 
      case 32: 
        if (
          !isViewerInPresentationMode &&
          pdfViewer.currentScaleValue !== "page-fit"
        ) {
          break;
        }
        if (PDFViewerApplication.page > 1) {
          PDFViewerApplication.page--;