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!
const groupCtx = this.ctx;
    this.groupLevel--;
    this.ctx = this.groupStack.pop();
    composeSMask(this.ctx, this.current.activeSMask, groupCtx);
    this.ctx.restore();
    this.ctx.save(); 
    copyCtxState(groupCtx, this.ctx);
    
    this.current.resumeSMaskCtx = groupCtx;
    
    
    const deltaTransform = Util.transform(
      this.current.activeSMask.startTransformInverse,
      groupCtx.mozCurrentTransform
    );
    this.ctx.transform.apply(this.ctx, deltaTransform);
    
    groupCtx.save();
    groupCtx.setTransform(1, 0, 0, 1, 0, 0);
    groupCtx.clearRect(0, 0, groupCtx.canvas.width, groupCtx.canvas.height);
    groupCtx.restore();
  }
  resumeSMaskGroup() {