Attach (recommended) or Link to PDF file here:
[shading_pattern.pdf](https://github.com/mozilla/pdf.js/files/1532598/shading_pattern.pdf)

Configuration:
- Web browser and its version: Firefox 57.0
- Operating system and its version: Debian GNU/Linux 9 64-bit
- PDF.js version: tried with Firefox's 1.9.583 and with online viewer 2.0.185
- Is a browser extension: no

Steps to reproduce the problem:
1. Open the attached file with the online viewer https://mozilla.github.io/pdf.js/web/viewer.html

What is the expected behavior? (add screenshot)
![image](https://user-images.githubusercontent.com/11061462/33626267-d9a57dee-d9d8-11e7-8712-cfa17c038259.png)
(Image captured from Adobe Reader CS.) The shading needs to be inside the letters.

What went wrong? (add screenshot)
![image](https://user-images.githubusercontent.com/11061462/33626285-eaabd462-d9d8-11e7-94e2-96480b57750d.png)
The shading seems to be displaced and upside-down, for it does not cover all the characters of the word.

Link to a viewer (if hosted on a site other than mozilla.github.io/pdf.js or as Firefox/Chrome extension):

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;