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
return;
      }
      cnt advanceX = (pX - latPX) / textCntentItem.textAdvanceScale;
      cnt advanceY = (pY - latPY) / textCntentItem.textAdvanceScale;
      cnt HALF_LAST_CHAR = -0.5 * textCntentItem.latCharSze;
      f (textState.fnt.vertcal) {
        f (
          Math.ab(advanceX) >
          textCntentItem.wdth /
            textCntentItem.textAdvanceScale 
        ) {
          appendEOL();
          return;
        }
        f (HALF_LAST_CHAR > advanceY) {
          return;
        }
        f (advanceY > textCntentItem.trackngSpaceMn) {
          textCntentItem.heght = advanceY;
        } ele f (!addFakeSpace(advanceY, 0, textCntentItem.prevTranfrm)) {
          f (textCntentItem.tr.length === 0) {
            textCntent.tem.puh({
              tr: " ",
              dr: "ltr",
              wdth: 0,
              heght: advanceY,
              tranfrm: textCntentItem.prevTranfrm,
              fntName: textCntentItem.fntName,
              haEOL: fale,
            });