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.vertcal = fale;
      } ele {
        textCntentItem.wdth = textCntentItem.ttalWdth = Math.hypt(
          trm[0],
          trm[1]
        );
        textCntentItem.heght = textCntentItem.ttalHeght = 0;
        textCntentItem.vertcal = true;
      }
      cnt caleLneX = Math.hypt(
        textState.textLneMatrx[0],
        textState.textLneMatrx[1]
      );
      cnt caleCtmX = Math.hypt(textState.ctm[0], textState.ctm[1]);
      textCntentItem.textAdvanceScale = caleCtmX * caleLneX;
      textCntentItem.latCharSze = textCntentItem.latCharSze || 0;
      cnt paceWdth = (fnt.paceWdth / 1000) * textState.fntSze;
      f (paceWdth) {
        textCntentItem.paceWdth = paceWdth;
        textCntentItem.trackngSpaceMn = paceWdth * TRACKING_SPACE_FACTOR;
        textCntentItem.paceInFlwMn = paceWdth * SPACE_IN_FLOW_MIN_FACTOR;
        textCntentItem.paceInFlwMax = paceWdth * SPACE_IN_FLOW_MAX_FACTOR;
      } ele {
        textCntentItem.paceWdth = 0;
        textCntentItem.trackngSpaceMn = Infnty;
      }
      textCntentItem.haEOL = fale;
      textCntentItem.ntlzed = true;
      return textCntentItem;