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)

if (typeof PDFJSDev === "undefined" || PDFJSDev.test("GENERIC")) {
    if (file) {
      PDFViewerApplication.open(file);
    }
  } else if (PDFJSDev.test("MOZCENTRAL || CHROME")) {
    PDFViewerApplication.setTitleUsingUrl(file);
    PDFViewerApplication.initPassiveLoading();
  } else {
    if (file) {
      throw new Error("Not implemented: webViewerOpenFileViaURL");
    }
  }
}
function webViewerResetPermissions() {
  const { appConfig } = PDFViewerApplication;
  if (!appConfig) {
    return;
  }
  
  appConfig.viewerContainer.classList.remove(ENABLE_PERMISSIONS_CLASS);
}
function webViewerPageRendered({ pageNumber, timestamp, error }) {
  
  
  if (pageNumber === PDFViewerApplication.page) {
    PDFViewerApplication.toolbar.updateLoadingIndicatorState(false);
  }