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
}
      const urlObj = new URL(
        TEST_PDFS_PATH + basicApiFileName,
        window.location
      );
      const loadingTask = getDocument(urlObj);
      expect(loadingTask instanceof PDFDocumentLoadingTask).toEqual(true);
      const pdfDocument = await loadingTask.promise;
      expect(urlObj instanceof URL).toEqual(true);
      expect(pdfDocument instanceof PDFDocumentProxy).toEqual(true);
      expect(pdfDocument.numPages).toEqual(3);
      await loadingTask.destroy();
    });
    it("creates pdf doc from URL", async function () {
      const loadingTask = getDocument(basicApiGetDocumentParams);
      expect(loadingTask instanceof PDFDocumentLoadingTask).toEqual(true);
      const progressReportedCapability = createPromiseCapability();
      
      
      loadingTask.onProgress = function (progressData) {
        if (!progressReportedCapability.settled) {
          progressReportedCapability.resolve(progressData);
        }
      };
      const data = await Promise.all([
        progressReportedCapability.promise,
        loadingTask.promise,
      ]);
      expect(data[0].loaded / data[0].total >= 0).toEqual(true);
      expect(data[1] instanceof PDFDocumentProxy).toEqual(true);