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):

strBuf.length = stringLength;
            for (i = 0; i < stringLength; ++i) {
              strBuf[i] = String.fromCharCode(font.getByte());
            }
            customNames.push(strBuf.join(""));
          }
          glyphNames = [];
          for (i = 0; i < numGlyphs; ++i) {
            const j = glyphNameIndexes[i];
            if (j < 258) {
              glyphNames.push(MacStandardGlyphOrdering[j]);
              continue;
            }
            glyphNames.push(customNames[j - 258]);
          }
          break;
        case 0x00030000:
          break;
        default:
          warn("Unknown/unsupported post table version " + version);
          valid = false;
          if (propertiesObj.defaultEncoding) {
            glyphNames = propertiesObj.defaultEncoding;
          }
          break;
      }
      propertiesObj.glyphNames = glyphNames;
      return valid;
    }
    function readNameTable(nameTable) {