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)

switch (evt.action) {
    case "GoToPage":
      PDFViewerApplication.appConfig.toolbar.pageNumber.select();
      break;
    case "Find":
      if (!PDFViewerApplication.supportsIntegratedFind) {
        PDFViewerApplication.findBar.toggle();
      }
      break;
    case "Print":
      PDFViewerApplication.triggerPrinting();
      break;
    case "SaveAs":
      webViewerSave();
      break;
  }
}
function webViewerPresentationModeChanged(evt) {