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)

renderTask.cancel();
      },
    };
    const viewport = this.viewport;
    const canvas = document.createElement("canvas");
    
    
    canvas.hidden = true;
    let isCanvasHidden = true;
    const showCanvas = function () {
      if (isCanvasHidden) {
        canvas.hidden = false;
        isCanvasHidden = false;
      }
    };
    canvasWrapper.appendChild(canvas);
    this.canvas = canvas;
    if (
      typeof PDFJSDev === "undefined" ||
      PDFJSDev.test("MOZCENTRAL || GENERIC")
    ) {
      canvas.mozOpaque = true;
    }
    const ctx = canvas.getContext("2d", { alpha: false });
    const outputScale = getOutputScale(ctx);
    this.outputScale = outputScale;
    if (this.useOnlyCssZoom) {
      const actualSizeViewport = viewport.clone({ scale: CSS_UNITS });