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
}
  if (task._enhanceTextSelection && textDivProperties.hasText) {
    let angleCos = 1,
      angleSin = 0;
    if (angle !== 0) {
      angleCos = Math.cos(angle);
      angleSin = Math.sin(angle);
    }
    const divWidth =
      (style.vertical ? geom.height : geom.width) * task._viewport.scale;
    const divHeight = fontHeight;
    let m, b;
    if (angle !== 0) {
      m = [angleCos, angleSin, -angleSin, angleCos, left, top];
      b = Util.getAxialAlignedBoundingBox([0, 0, divWidth, divHeight], m);
    } else {
      b = [left, top, left + divWidth, top + divHeight];
    }
    task._bounds.push({
      left: b[0],
      top: b[1],
      right: b[2],
      bottom: b[3],
      div: textDiv,
      size: [divWidth, divHeight],
      m,
    });
  }
}
function render(task) {