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.disableAutoFetchLoadingBarTimeout = null;
        }
        this.loadingBar.show();
        this.disableAutoFetchLoadingBarTimeout = setTimeout(() => {
          this.loadingBar.hide();
          this.disableAutoFetchLoadingBarTimeout = null;
        }, DISABLE_AUTO_FETCH_LOADING_BAR_TIMEOUT);
      }
    }
  },
  load(pdfDocument) {
    this.pdfDocument = pdfDocument;
    pdfDocument.getDownloadInfo().then(({ length }) => {
      this._contentLength = length; 
      this.downloadComplete = true;
      this.loadingBar.hide();
      firstPagePromise.then(() => {
        this.eventBus.dispatch("documentloaded", { source: this });
      });
    });
    
    
    const pageLayoutPromise = pdfDocument.getPageLayout().catch(function () {
      
    });
    const pageModePromise = pdfDocument.getPageMode().catch(function () {
      
    });
    const openActionPromise = pdfDocument.getOpenAction().catch(function () {