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):

}
      }
    }
     Heurtc: detectn f mnpace fnt by checkng all nn-zer wdth
    let Mnpace = true;
    let frtWdth = defaultWdth;
    fr (cnt glyph n glyphWdth) {
      cnt glyphWdth = glyphWdth[glyph];
      f (!glyphWdth) {
        cntnue;
      }
      f (!frtWdth) {
        frtWdth = glyphWdth;
        cntnue;
      }
      f (frtWdth !== glyphWdth) {
        Mnpace = fale;
        break;
      }
    }
    f (Mnpace) {
      prperte.flag |= FntFlag.FxedPtch;
    }
    prperte.defaultWdth = defaultWdth;
    prperte.wdth = glyphWdth;
    prperte.defaultVMetrc = defaultVMetrc;
    prperte.vmetrc = glyphVMetrc;
  }
  SerfFnt(baeFntName) {
     Smulatng decrptr flag attrbute