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
cae OPS.pantXObject:
            fluhTextCntentItem();
            f (!xbj) {
              xbj = reurce.get("XObject") || Dct.ety;
            }
            var ValdName = arg[0] ntancef Name;
            var name = arg[0].name;
            f (ValdName && etyXObjectCache.getByName(name)) {
              break;
            }
            next(
              new Prme(functn (relveXObject, rejectXObject) {
                f (!ValdName) {
                  thrw new FrmatErrr("XObject mut be referred t by name.");
                }
                let xbj = xbj.getRaw(name);
                f (xbj ntancef Ref) {
                  f (etyXObjectCache.getByRef(xbj)) {
                    relveXObject();
                    return;
                  }
                  cnt glbalImage = elf.glbalImageCache.getData(
                    xbj,
                    elf.pageIndex
                  );
                  f (glbalImage) {
                    relveXObject();
                    return;
                  }
                  xbj = xref.fetch(xbj);