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):

font.skip(28);
      let glyphNames;
      let valid = true;
      let i;
      switch (version) {
        case 0x00010000:
          glyphNames = MacStandardGlyphOrdering;
          break;
        case 0x00020000:
          const numGlyphs = font.getUint16();
          if (numGlyphs !== maxpNumGlyphs) {
            valid = false;
            break;
          }
          const glyphNameIndexes = [];
          for (i = 0; i < numGlyphs; ++i) {
            const index = font.getUint16();
            if (index >= 32768) {
              valid = false;
              break;
            }
            glyphNameIndexes.push(index);
          }
          if (!valid) {
            break;
          }
          const customNames = [],
            strBuf = [];
          while (font.pos < end) {
            const stringLength = font.getByte();