Link to PDF file (or attach file here):
[pages4.pdf](https://github.com/mozilla/pdf.js/files/1128300/pages4.pdf)

Configuration:
- Web browser and its version: Firefox 54
- Operating system and its version: Win 10
- PDF.js version: 1.8.522
- Is an extension: no

What is the expected behavior? (add screenshot)
![chrome1-1 1](https://user-images.githubusercontent.com/146436/27918380-2f74512a-6245-11e7-8525-d0038fa6c2e8.jpg)
![chrome1-2 1](https://user-images.githubusercontent.com/146436/27918425-54f8e47e-6245-11e7-9bff-127f79ad0511.jpg)


What went wrong? (add screenshot)
![screenshot from 2017-07-06 12-10-30](https://user-images.githubusercontent.com/146436/27918442-5d57624e-6245-11e7-9436-5ba31cc8bd1a.png)
![screenshot from 2017-07-06 12-10-44](https://user-images.githubusercontent.com/146436/27918454-63b486da-6245-11e7-9eb5-c03aa5c40943.png)



this.current.leading = -leading;
  }
  setFont(fontRefName, size) {
    const fontObj = this.commonObjs.get(fontRefName);
    const current = this.current;
    if (!fontObj) {
      throw new Error(`Can't find font for ${fontRefName}`);
    }
    current.fontMatrix = fontObj.fontMatrix || FONT_IDENTITY_MATRIX;
    
    
    if (current.fontMatrix[0] === 0 || current.fontMatrix[3] === 0) {
      warn("Invalid font matrix for font " + fontRefName);
    }
    
    
    if (size < 0) {
      size = -size;
      current.fontDirection = -1;
    } else {
      current.fontDirection = 1;
    }
    this.current.font = fontObj;
    this.current.fontSize = size;
    if (fontObj.isType3Font) {
      return; 
    }
    const name = fontObj.loadedName || "sans-serif";
    let bold = "normal";
    if (fontObj.black) {