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 length = arr.length;
  
  if (length === 1 && arr[0] instanceof Uint8Array) {
    return arr[0];
  }
  let resultLength = 0;
  for (let i = 0; i < length; i++) {
    resultLength += arrayByteLength(arr[i]);
  }
  let pos = 0;
  const data = new Uint8Array(resultLength);
  for (let i = 0; i < length; i++) {
    let item = arr[i];
    if (!(item instanceof Uint8Array)) {
      if (typeof item === "string") {
        item = stringToBytes(item);
      } else {
        item = new Uint8Array(item);
      }
    }
    const itemLength = item.byteLength;
    data.set(item, pos);
    pos += itemLength;
  }
  return data;
}
function string32(value) {