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): ?

this.setLeading(-y);
    this.moveText(x, y);
  }
  setTextMatrix(a, b, c, d, e, f) {
    this.current.textMatrix = [a, b, c, d, e, f];
    this.current.textMatrixScale = Math.hypot(a, b);
    this.current.x = this.current.lineX = 0;
    this.current.y = this.current.lineY = 0;
  }
  nextLine() {
    this.moveText(0, this.current.leading);
  }
  paintChar(character, x, y, patternTransform, resetLineWidthToOne) {
    const ctx = this.ctx;
    const current = this.current;
    const font = current.font;
    const textRenderingMode = current.textRenderingMode;
    const fontSize = current.fontSize / current.fontSizeScale;
    const fillStrokeMode =
      textRenderingMode & TextRenderingMode.FILL_STROKE_MASK;
    const isAddToPathSet = !!(
      textRenderingMode & TextRenderingMode.ADD_TO_PATH_FLAG
    );
    const patternFill = current.patternFill && !font.missingFile;
    let addToPath;
    if (font.disableFontFace || isAddToPathSet || patternFill) {
      addToPath = font.getPathGenerator(this.commonObjs, character);
    }