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!
scaleX = drawnWidth / MAX_GROUP_SIZE;
      drawnWidth = MAX_GROUP_SIZE;
    }
    if (drawnHeight > MAX_GROUP_SIZE) {
      scaleY = drawnHeight / MAX_GROUP_SIZE;
      drawnHeight = MAX_GROUP_SIZE;
    }
    let cacheId = "groupAt" + this.groupLevel;
    if (group.smask) {
      
      cacheId += "_smask_" + (this.smaskCounter++ % 2);
    }
    const scratchCanvas = this.cachedCanvases.getCanvas(
      cacheId,
      drawnWidth,
      drawnHeight,
      true
    );
    const groupCtx = scratchCanvas.context;
    
    
    groupCtx.scale(1 / scaleX, 1 / scaleY);
    groupCtx.translate(-offsetX, -offsetY);
    groupCtx.transform.apply(groupCtx, currentTransform);
    if (group.smask) {
      
      this.smaskStack.push({
        canvas: scratchCanvas.canvas,
        context: groupCtx,
        offsetX,