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)

});
    this.toolbar.setPagesCount(pdfDocument.numPages, false);
    this.secondaryToolbar.setPagesCount(pdfDocument.numPages);
    let baseDocumentUrl;
    if (typeof PDFJSDev === "undefined" || PDFJSDev.test("GENERIC")) {
      baseDocumentUrl = null;
    } else if (PDFJSDev.test("MOZCENTRAL")) {
      baseDocumentUrl = this.baseUrl;
    } else if (PDFJSDev.test("CHROME")) {
      baseDocumentUrl = location.href.split("#")[0];
    }
    this.pdfLinkService.setDocument(pdfDocument, baseDocumentUrl);
    this.pdfDocumentProperties.setDocument(pdfDocument, this.url);
    const pdfViewer = this.pdfViewer;
    pdfViewer.setDocument(pdfDocument);
    const { firstPagePromise, onePageRendered, pagesPromise } = pdfViewer;
    const pdfThumbnailViewer = this.pdfThumbnailViewer;
    pdfThumbnailViewer.setDocument(pdfDocument);
    const storedPromise = (this.store = new ViewHistory(
      pdfDocument.fingerprint
    ))
      .getMultiple({
        page: null,
        zoom: DEFAULT_SCALE_VALUE,
        scrollLeft: "0",
        scrollTop: "0",
        rotation: null,
        sidebarView: SidebarView.UNKNOWN,
        scrollMode: ScrollMode.UNKNOWN,
        spreadMode: SpreadMode.UNKNOWN,