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 {
        canvasContext,
        viewport,
        transform,
        imageLayer,
        background,
      } = this.params;
      this.gfx = new CanvasGraphics(
        canvasContext,
        this.commonObjs,
        this.objs,
        this.canvasFactory,
        this.webGLContext,
        imageLayer,
        optionalContentConfig
      );
      this.gfx.beginDrawing({
        transform,
        viewport,
        transparency,
        background,
      });
      this.operatorListIdx = 0;
      this.graphicsReady = true;
      if (this.graphicsReadyCallback) {
        this.graphicsReadyCallback();
      }
    }
    cancel(error = null) {