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): ?

let pattern;
    if (this.cachedPatterns.has(objId)) {
      pattern = this.cachedPatterns.get(objId);
    } else {
      pattern = getShadingPattern(
        this.objs.get(objId),
        this.cachedCanvasPatterns
      );
      this.cachedPatterns.set(objId, pattern);
    }
    if (matrix) {
      pattern.matrix = matrix;
    }
    return pattern;
  }
  shadingFill(objId) {
    if (!this.contentVisible) {
      return;
    }
    const ctx = this.ctx;
    this.save();
    const pattern = this._getPattern(objId);
    ctx.fillStyle = pattern.getPattern(
      ctx,
      this,
      ctx.mozCurrentTransformInverse,
      true