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)

constructor(
      canvasCtx,
      commonObjs,
      objs,
      canvasFactory,
      webGLContext,
      imageLayer,
      optionalContentConfig
    ) {
      this.ctx = canvasCtx;
      this.current = new CanvasExtraState();
      this.stateStack = [];
      this.pendingClip = null;