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)

url: source.url,
        password: source.password,
        disableAutoFetch: source.disableAutoFetch,
        rangeChunkSize: source.rangeChunkSize,
        length: source.length,
      },
      maxImageSize: source.maxImageSize,
      disableFontFace: source.disableFontFace,
      postMessageTransfers: worker.postMessageTransfers,
      docBaseUrl: source.docBaseUrl,
      ignoreErrors: source.ignoreErrors,
      isEvalSupported: source.isEvalSupported,
      fontExtraProperties: source.fontExtraProperties,
      enableXfa: source.enableXfa,
    })
    .then(function (workerId) {
      if (worker.destroyed) {
        throw new Error("Worker was destroyed");
      }
      return workerId;
    });
}
/**
 * The loading task controls the operations required to load a PDF document
 * (such as network requests) and provides a way to listen for completion,
 * after which individual pages can be rendered.
 *
 * @typedef {Object} PDFDocumentLoadingTask
 * @property {string} docId - Unique identifier for the document loading task.
 * @property {boolean} destroyed - Whether the loading task is destroyed or not.