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)


if (ex instanceof MissingDataException) {
        throw ex;
      }
      warn(`XRef.parse - Invalid "Encrypt" reference: "${ex}".`);
    }
    if (encrypt instanceof Dict) {
      const ids = trailerDict.get("ID");
      const fileId = ids && ids.length ? ids[0] : "";
      
      
      
      
      encrypt.suppressEncryption = true;
      this.encrypt = new CipherTransformFactory(
        encrypt,
        fileId,
        this.pdfManager.password
      );
    }
    
    let root;
    try {
      root = trailerDict.get("Root");
    } catch (ex) {
      if (ex instanceof MissingDataException) {
        throw ex;
      }
      warn(`XRef.parse - Invalid "Root" reference: "${ex}".`);
    }
    if (root instanceof Dict) {