Attach (recommended) or Link to PDF file here: https://www.recom-power.com/pdf/Powerline-AC-DC/RAC05-K.pdf

Configuration:
- Web browser and its version: Firefox 56.0 (64-bit)
- Operating system and its version: Windows 10 with OS Build 15063.632
- PDF.js version: ?
- Is an extension: Built-in

Steps to reproduce the problem:
1. Open Page

What is the expected behavior? To properly render the first page. 
![image](https://user-images.githubusercontent.com/1151969/31415345-b1504022-add7-11e7-855b-8030a308f7a2.png)

What went wrong? Renders poorly.
![image](https://user-images.githubusercontent.com/1151969/31415363-d8842096-add7-11e7-818d-728c1102891b.png)

Link to a viewer (if hosted on a site other than mozilla.github.io/pdf.js or as Firefox/Chrome extension): ?

bold = "900";
    } else if (fontObj.bold) {
      bold = "bold";
    }
    const italic = fontObj.italic ? "italic" : "normal";
    const typeface = `"${name}", ${fontObj.fallbackName}`;
    
    
    
    
    let browserFontSize = size;
    if (size < MIN_FONT_SIZE) {
      browserFontSize = MIN_FONT_SIZE;
    } else if (size > MAX_FONT_SIZE) {
      browserFontSize = MAX_FONT_SIZE;
    }
    this.current.fontSizeScale = size / browserFontSize;
    this.ctx.font = `${italic} ${bold} ${browserFontSize}px ${typeface}`;
  }
  setTextRenderingMode(mode) {
    this.current.textRenderingMode = mode;
  }
  setTextRise(rise) {
    this.current.textRise = rise;
  }
  moveText(x, y) {
    this.current.x = this.current.lineX += x;
    this.current.y = this.current.lineY += y;
  }
  setLeadingMoveText(x, y) {