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!
case "BM":
          this.ctx.globalCompositeOperation = value;
          break;
        case "SMask":
          if (this.current.activeSMask) {
            
            
            
            if (
              this.stateStack.length > 0 &&
              this.stateStack[this.stateStack.length - 1].activeSMask ===
                this.current.activeSMask
            ) {
              this.suspendSMaskGroup();
            } else {
              this.endSMaskGroup();
            }
          }
          this.current.activeSMask = value ? this.tempSMask : null;
          if (this.current.activeSMask) {
            this.beginSMaskGroup();
          }
          this.tempSMask = null;
          break;
        case "TR":
          this.current.transferMaps = value;
      }
    }
  }
  beginSMaskGroup() {