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)

if (!isWorkerDisabled) {
        warn("Setting up fake worker.");
        isWorkerDisabled = true;
      }
      setupFakeWorkerGlobal()
        .then(WorkerMessageHandler => {
          if (this.destroyed) {
            this._readyCapability.reject(new Error("Worker was destroyed"));
            return;
          }
          const port = new LoopbackPort();
          this._port = port;
          
          const id = "fake" + nextFakeWorkerId++;
          
          
          const workerHandler = new MessageHandler(id + "_worker", id, port);
          WorkerMessageHandler.setup(workerHandler, port);
          const messageHandler = new MessageHandler(id, id + "_worker", port);
          this._messageHandler = messageHandler;
          this._readyCapability.resolve();
          
          messageHandler.send("configure", {
            verbosity: this.verbosity,