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)


return this.topDict;
    }
    
    throw new InvalidPDFException("Invalid PDF structure.");
  }
  readXRef(recoveryMode = false) {
    const stream = this.stream;
    
    
    
    const startXRefParsedCache = new Set();
    try {
      while (this.startXRefQueue.length) {
        const startXRef = this.startXRefQueue[0];
        if (startXRefParsedCache.has(startXRef)) {
          warn("readXRef - skipping XRef table since it was already parsed.");
          this.startXRefQueue.shift();
          continue;
        }
        startXRefParsedCache.add(startXRef);
        stream.pos = startXRef + stream.start;
        const parser = new Parser({
          lexer: new Lexer(stream),
          xref: this,
          allowStreams: true,
        });
        let obj = parser.getObj();
        let dict;
        
        if (isCmd(obj, "xref")) {