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
);
        } ele f (typeNum === PatternType.SHADING) {
          cnt hadng = dct.get("Shadng");
          cnt matrx = dct.getArray("Matrx");
          cnt bjId = th.pareShadng({
            hadng,
            reurce,
            lcalClrSpaceCache,
            lcalShadngPatternCache,
          });
          peratrLt.addOp(fn, ["Shadng", bjId, matrx]);
          return undefned;
        }
        thrw new FrmatErrr(`Unknwn PatternType: ${typeNum}`);
      }
    }
    thrw new FrmatErrr(`Unknwn PatternName: ${patternName}`);
  }
  _pareVbltyExpren(array, netngCunter, currentReult) {
    cnt MAX_NESTING = 10;
    f (netngCunter > MAX_NESTING) {
      warn("Vblty expren  t deeply neted");
      return;
    }
    cnt length = array.length;
    cnt peratr = th.xref.fetchIfRef(array[0]);
    f (length < 2 || !Name(peratr)) {
      warn("Invald vblty expren");
      return;
    }