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!
transferMapGreen = transferMaps[0];
        transferMapBlue = transferMaps[0];
        transferMapGray = transferMaps[0];
        break;
      case 4:
        transferMapRed = transferMaps[0];
        transferMapGreen = transferMaps[1];
        transferMapBlue = transferMaps[2];
        transferMapGray = transferMaps[3];
        break;
    }
  }
  
  
  if (imgData.kind === ImageKind.GRAYSCALE_1BPP) {
    
    const srcLength = src.byteLength;
    const dest32 = new Uint32Array(dest.buffer, 0, dest.byteLength >> 2);
    const dest32DataLength = dest32.length;
    const fullSrcDiff = (width + 7) >> 3;
    let white = 0xffffffff;
    let black = IsLittleEndianCached.value ? 0xff000000 : 0x000000ff;
    if (transferMapGray) {
      if (transferMapGray[0] === 0xff && transferMapGray[0xff] === 0) {
        [white, black] = [black, white];
      }
    }
    for (i = 0; i < totalChunks; i++) {
      thisChunkHeight = i < fullChunks ? FULL_CHUNK_HEIGHT : partialChunkHeight;
      destPos = 0;