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)

return this._pagesRotation;
  }
  /**
   * @param {number} rotation - The rotation of the pages (0, 90, 180, 270).
   */
  set pagesRotation(rotation) {
    if (!isValidRotation(rotation)) {
      throw new Error("Invalid pages rotation angle.");
    }
    if (!this.pdfDocument) {
      return;
    }
    
    rotation %= 360;
    if (rotation < 0) {
      rotation += 360;
    }
    if (this._pagesRotation === rotation) {
      return; 
    }
    this._pagesRotation = rotation;
    const pageNumber = this._currentPageNumber;
    for (let i = 0, ii = this._pages.length; i < ii; i++) {