Trying to read a pdf file using PDFJS.getDocument function. The pdf worker is throwing


UnknownErrorException {
 name: "UnknownErrorException", 
 message: "Invalid root reference", 
 details: "FormatError: Invalid root reference"
}

The error can be easily reproduced calling PDFJS.getDocument(pdfUrl) using the attached pdf
[110229_10312017_6810306.pdf](https://github.com/mozilla/pdf.js/files/1444166/110229_10312017_6810306.pdf)


this._cacheMap.set(num, xrefEntry);
      return xrefEntry;
    }
    
    
    if (this._pendingRefs.has(ref)) {
      this._pendingRefs.remove(ref);
      warn(`Ignoring circular reference: ${ref}.`);
      return CIRCULAR_REF;
    }
    this._pendingRefs.put(ref);
    try {
      if (xrefEntry.uncompressed) {
        xrefEntry = this.fetchUncompressed(ref, xrefEntry, suppressEncryption);
      } else {
        xrefEntry = this.fetchCompressed(ref, xrefEntry, suppressEncryption);
      }
      this._pendingRefs.remove(ref);
    } catch (ex) {
      this._pendingRefs.remove(ref);
      throw ex;
    }
    if (xrefEntry instanceof Dict) {
      xrefEntry.objId = ref.toString();
    } else if (xrefEntry instanceof BaseStream) {
      xrefEntry.dict.objId = ref.toString();
    }
    return xrefEntry;
  }
  fetchUncompressed(ref, xrefEntry, suppressEncryption = false) {