Link to PDF file (or attach file here):
[RP_25884_V2_UEL Semi Finals 2016-17_concepts.pdf](https://github.com/mozilla/pdf.js/files/994423/RP_25884_V2_UEL.Semi.Finals.2016-17_concepts.pdf)

Configuration:
- Web browser and its version: Chrome 58, Firefox 53
- Operating system and its version: MacOS 10.11.6
- PDF.js version:
- Is an extension: No

Steps to reproduce the problem:
1.  View the file the file


What is the expected behavior? (add screenshot)
<img width="560" alt="screen shot 2017-05-11 at 2 06 36 pm" src="https://cloud.githubusercontent.com/assets/2474027/25971992/189f4ebe-3653-11e7-8847-c9011984cb8d.png">

What went wrong? (add screenshot)
Textlayer exists here but font fails to render. No warning in the console from what I can see. Maybe related to the gradient?

<img width="637" alt="screen shot 2017-05-11 at 2 06 20 pm" src="https://cloud.githubusercontent.com/assets/2474027/25971997/1b518cc6-3653-11e7-96c0-9a03ffcb7d6e.png">

Thanks!
unreachable("Should not call beginImageData");
  }
  paintFormXObjectBegin(matrix, bbox) {
    if (!this.contentVisible) {
      return;
    }
    this.save();
    this.baseTransformStack.push(this.baseTransform);
    if (Array.isArray(matrix) && matrix.length === 6) {
      this.transform.apply(this, matrix);
    }
    this.baseTransform = this.ctx.mozCurrentTransform;
    if (bbox) {
      const width = bbox[2] - bbox[0];
      const height = bbox[3] - bbox[1];
      this.ctx.rect(bbox[0], bbox[1], width, height);
      this.clip();
      this.endPath();
    }
  }
  paintFormXObjectEnd() {
    if (!this.contentVisible) {
      return;
    }
    this.restore();
    this.baseTransform = this.baseTransformStack.pop();
  }
  beginGroup(group) {