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):

header31012 +
    format31012
  );
}
function validateOS2Table(os2, file) {
  file.pos = (file.start || 0) + os2.offset;
  const version = file.getUint16();
  
  
  file.skip(60); 
  const selection = file.getUint16();
  if (version < 4 && selection & 0x0300) {
    return false;
  }
  const firstChar = file.getUint16();
  const lastChar = file.getUint16();
  if (firstChar > lastChar) {
    return false;
  }
  file.skip(6); 
  const usWinAscent = file.getUint16();
  if (usWinAscent === 0) {
    
    return false;
  }
  
  os2.data[8] = os2.data[9] = 0; 
  return true;
}
function createOS2Table(properties, charstrings, override) {