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.pdfLinkService = pdfLinkService;
    const downloadManager = this.externalServices.createDownloadManager();
    this.downloadManager = downloadManager;
    const findController = new PDFFindController({
      linkService: pdfLinkService,
      eventBus,
    });
    this.findController = findController;
    const pdfScriptingManager = new PDFScriptingManager({
      eventBus,
      sandboxBundleSrc:
        typeof PDFJSDev === "undefined" ||
        PDFJSDev.test("!PRODUCTION || GENERIC || CHROME")
          ? AppOptions.get("sandboxBundleSrc")
          : null,
      scriptingFactory: this.externalServices,
      docPropertiesLookup: this._scriptingDocProperties.bind(this),
    });
    this.pdfScriptingManager = pdfScriptingManager;
    const container = appConfig.mainContainer;
    const viewer = appConfig.viewerContainer;
    this.pdfViewer = new PDFViewer({
      container,
      viewer,
      eventBus,
      renderingQueue: pdfRenderingQueue,
      linkService: pdfLinkService,
      downloadManager,
      findController,
      scriptingManager: pdfScriptingManager,