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 permissions = await pdfDocument.getPermissions();
    if (pdfDocument !== this.pdfDocument) {
      return; 
    }
    if (!permissions || !AppOptions.get("enablePermissions")) {
      return;
    }
    
    if (!permissions.includes(PermissionFlag.COPY)) {
      this.appConfig.viewerContainer.classList.add(ENABLE_PERMISSIONS_CLASS);
    }
  },
  /**
   * @private
   */
  _initializeAnnotationStorageCallbacks(pdfDocument) {