Attach (recommended) or Link to PDF file here:
[298865.pdf](https://github.com/mozilla/pdf.js/files/2753236/298865.pdf)


Configuration:
- Web browser and its version:chrome 71.0.3578.98
- Operating system and its version:mac os 10.12.6
- PDF.js version:I use online demo in github
- Is a browser extension:no

Steps to reproduce the problem:
1. search "中华" or "电力" or so on,the highlight position is not right

What is the expected behavior? (add screenshot)
![image](https://user-images.githubusercontent.com/10000986/51087378-7eff5100-178d-11e9-991a-005d77b82f31.png)

What went wrong? (add screenshot)
![image](https://user-images.githubusercontent.com/10000986/51087374-6ee77180-178d-11e9-9707-281924f95fd0.png)

Link to a viewer (if hosted on a site other than mozilla.github.io/pdf.js or as Firefox/Chrome extension):
https://mozilla.github.io/pdf.js/web/viewer.html
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,