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 = new Stream(new Uint8Array(font.getBytes()));
    let header, tables;
    if (isTrueTypeCollectionFile(font)) {
      const ttcData = readTrueTypeCollectionData(font, this.name);
      header = ttcData.header;
      tables = ttcData.tables;
    } else {
      header = readOpenTypeHeader(font);
      tables = readTables(font, header.numTables);
    }
    let cff, cffFile;
    const isTrueType = !tables["CFF "];
    if (!isTrueType) {
      const isComposite =
        properties.composite &&
        ((properties.cidToGidMap || []).length > 0 ||
          !(properties.cMap instanceof IdentityCMap));
      
      if (
        (header.version === "OTTO" && !isComposite) ||
        !tables.head ||
        !tables.hhea ||
        !tables.maxp ||
        !tables.post
      ) {
        
        cffFile = new Stream(tables["CFF "].data);
        cff = new CFFFont(cffFile, properties);
        adjustWidths(properties);
        return this.convert(name, cff, properties);