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 (generationByte === -1) {
            throw new FormatError("Invalid XRef byteWidths 'generation'.");
          }
          generation = (generation << 8) | generationByte;
        }
        const entry = {};
        entry.offset = offset;
        entry.gen = generation;
        switch (type) {
          case 0:
            entry.free = true;
            break;
          case 1:
            entry.uncompressed = true;
            break;
          case 2:
            break;
          default:
            throw new FormatError(`Invalid XRef entry type: ${type}`);
        }
        if (!this.entries[first + i]) {
          this.entries[first + i] = entry;
        }
      }
      streamState.entryNum = 0;
      streamState.streamPos = stream.pos;
      entryRanges.splice(0, 2);
    }
  }
  indexObjects() {