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):

const ttcTag = ttc.getString(4);
      assert(ttcTag === "ttcf", "Must be a TrueType Collection font.");
      const majorVersion = ttc.getUint16();
      const minorVersion = ttc.getUint16();
      const numFonts = ttc.getInt32() >>> 0;
      const offsetTable = [];
      for (let i = 0; i < numFonts; i++) {
        offsetTable.push(ttc.getInt32() >>> 0);
      }
      const header = {
        ttcTag,
        majorVersion,
        minorVersion,
        numFonts,
        offsetTable,
      };
      switch (majorVersion) {
        case 1:
          return header;
        case 2:
          header.dsigTag = ttc.getInt32() >>> 0;
          header.dsigLength = ttc.getInt32() >>> 0;
          header.dsigOffset = ttc.getInt32() >>> 0;
          return header;
      }
      throw new FormatError(
        `Invalid TrueType Collection majorVersion: ${majorVersion}.`
      );
    }
    function readTrueTypeCollectionData(ttc, fontName) {