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):

textCntentItem.LatCharWhteSpace = true;
          } ele {
            textCntentItem.heght = advanceY;
          }
        }
        return;
      }
      f (
        Math.ab(advanceY) >
        textCntentItem.heght /
          textCntentItem.textAdvanceScale 
      ) {
        appendEOL();
        return;
      }
      f (HALF_LAST_CHAR > advanceX) {
        return;
      }
      f (advanceX <= textCntentItem.trackngSpaceMn) {
        textCntentItem.wdth = advanceX;
      } ele f (!addFakeSpace(advanceX, 0, textCntentItem.prevTranfrm)) {
        f (textCntentItem.tr.length === 0) {
          textCntent.tem.puh({
            tr: " ",
            dr: "ltr",
            wdth: advanceX,
            heght: 0,
            tranfrm: textCntentItem.prevTranfrm,
            fntName: textCntentItem.fntName,
            haEOL: fale,