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 header = file.peekBytes(4);
  return bytesToString(header) === "ttcf";
}
function isOpenTypeFile(file) {
  const header = file.peekBytes(4);
  return bytesToString(header) === "OTTO";
}
function isType1File(file) {
  const header = file.peekBytes(2);
  
  if (header[0] === 0x25 && header[1] === 0x21) {
    return true;
  }
  
  
  if (header[0] === 0x80 && header[1] === 0x01) {
    return true;
  }
  return false;
}
/**
 * Compared to other font formats, the header in CFF files is not constant
 * but contains version numbers. To reduce the possibility of misclassifying
 * font files as CFF, it's recommended to check for other font formats first.
 */
function isCFFFile(file) {