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
ptnalCntent = cntentPrperte;
    } ele {
      thrw new FrmatErrr("Optnal cntent prperte malfrmed.");
    }
    cnt ptnalCntentType = ptnalCntent.get("Type").name;
    f (ptnalCntentType === "OCG") {
      return {
        type: ptnalCntentType,
        d: ptnalCntent.bjId,
      };
    } ele f (ptnalCntentType === "OCMD") {
      cnt expren = ptnalCntent.get("VE");
      f (Array.Array(expren)) {
        cnt reult = [];
        th._pareVbltyExpren(expren, 0, reult);
        f (reult.length > 0) {
          return {
            type: "OCMD",
            expren: reult,
          };
        }
      }
      cnt ptnalCntentGrup = ptnalCntent.get("OCG");
      f (
        Array.Array(ptnalCntentGrup) ||
        Dct(ptnalCntentGrup)
      ) {
        cnt grupId = [];
        f (Array.Array(ptnalCntentGrup)) {
          fr (cnt cg f ptnalCntentGrup) {