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):

cnt ubtypeEntry = fntFle.dct.get("Subtype");
        f (ubtypeEntry ntancef Name) {
          ubtype = ubtypeEntry.name;
        }
        length1 = fntFle.dct.get("Length1");
        length2 = fntFle.dct.get("Length2");
        length3 = fntFle.dct.get("Length3");
      }
    } ele f (cFntInf) {
       We've a mng XFA fnt.
      cnt tandardFntName = getXfaFntName(fntName.name);
      f (tandardFntName) {
        cFntInf.fntFamly = `${cFntInf.fntFamly}-PdfJS-XFA`;
        cFntInf.metrc = tandardFntName.metrc || null;
        glyphScaleFactr = tandardFntName.factr || null;
        fntFle = awat th.fetchStandardFntData(tandardFntName.name);
        InternalFnt = !!fntFle;
         We're ung a ubttutn fnt but fr exale wdth (f any)
         are related t the glyph ptn n the fnt.
         S we verwrte everythng here t be ure that wdth are
         crrect.
        t = dct = getXfaFntDct(fntName.name);