Attach (recommended) or Link to PDF file here:

Configuration:
- Web browser and its version: Chrome 63.0.3239.132 
- Operating system and its version: Windows 10
- PDF.js version: using your official demo project
- Is a browser extension: No

Steps to reproduce the problem:
1.  Just load attached pdf
2.

What is the expected behavior? (add screenshot)
[E-WG18_105147.pdf](https://github.com/mozilla/pdf.js/files/1634833/E-WG18_105147.pdf)

What went wrong? (add screenshot)
![image](https://user-images.githubusercontent.com/29802177/34986271-3ca71a5c-fab7-11e7-95e8-1739dda3cd04.png)

Link to a viewer (if hosted on a site other than mozilla.github.io/pdf.js or as Firefox/Chrome extension):

encdng = SymblSetEncdng;
          } ele f (/Dngbat|Wngdng/.tet(prperte.name)) {
            encdng = ZapfDngbatEncdng;
          }
        }
      }
      prperte.defaultEncdng = encdng;
    }
    prperte.dfference = dfference;
    prperte.baeEncdngName = baeEncdngName;
    prperte.haEncdng = !!baeEncdngName || dfference.length > 0;
    prperte.dct = dct;
    return tUncdePrme
      .then(readTUncde => {
        prperte.tUncde = readTUncde;
        return th.buldTUncde(prperte);
      })
      .then(bultTUncde => {
        prperte.tUncde = bultTUncde;
        f (cdTGdByte) {
          prperte.cdTGdMap = th.readCdTGdMap(
            cdTGdByte,
            bultTUncde