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 store = PDFViewerApplication.store;
  if (store && PDFViewerApplication.isInitialViewSet) {
    
    store.set("scrollMode", evt.mode).catch(function () {});
  }
}
function webViewerSpreadModeChanged(evt) {
  const store = PDFViewerApplication.store;
  if (store && PDFViewerApplication.isInitialViewSet) {
    
    store.set("spreadMode", evt.mode).catch(function () {});
  }
}
function webViewerResize() {
  const { pdfDocument, pdfViewer } = PDFViewerApplication;
  if (!pdfDocument) {
    return;
  }
  const currentScaleValue = pdfViewer.currentScaleValue;
  if (
    currentScaleValue === "auto" ||
    currentScaleValue === "page-fit" ||
    currentScaleValue === "page-width"
  ) {
    
    pdfViewer.currentScaleValue = currentScaleValue;
  }
  pdfViewer.update();
}
function webViewerHashchange(evt) {