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): ?

imgData,
    scaleX,
    skewX = 0,
    skewY = 0,
    scaleY,
    positions
  ) {
    if (!this.contentVisible) {
      return;
    }
    const ctx = this.ctx;
    ctx.save();
    const currentTransform = ctx.mozCurrentTransform;
    ctx.transform(scaleX, skewX, skewY, scaleY, 0, 0);
    const mask = this._createMaskCanvas(imgData);
    ctx.setTransform(1, 0, 0, 1, 0, 0);
    for (let i = 0, ii = positions.length; i < ii; i += 2) {
      const trans = Util.transform(currentTransform, [
        scaleX,
        skewX,
        skewY,