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)


const rootDict = dict.get("Root");
        if (!(rootDict instanceof Dict)) {
          continue;
        }
        const pagesDict = rootDict.get("Pages");
        if (!(pagesDict instanceof Dict)) {
          continue;
        }
        const pagesCount = pagesDict.get("Count");
        if (!Number.isInteger(pagesCount)) {
          continue;
        }
        
      } catch (ex) {
        trailerError = ex;
        continue;
      }
      
      if (dict.has("ID")) {
        return dict;
      }
      
      trailerDict = dict;
    }
    
    if (trailerDict) {
      return trailerDict;
    }
    
    if (this.topDict) {