Here, i have attached the PDF, that PDF document contains "Nudi" as an embedded font. When i searching the particular word (that in Nudi font), the search result selecting the word that context next to the exact word.

Link to PDF file (or attach file here):
[sample_pdf.zip](https://github.com/mozilla/pdf.js/files/229582/sample_pdf.zip)

Configuration:
- Web browser and its version: Mozilla 45.0.2
- Operating system and its version: Windows 7
- PDF.js version: 1.4.20-disc

What is the expected behavior? (add screenshot)
![find_01](https://cloud.githubusercontent.com/assets/17423938/14704922/c2e67f2c-07d4-11e6-9320-9aed2578d377.png)

this.cancel();
    this.textContentStream = readableStream;
  }
  setTextContent(textContent) {
    this.cancel();
    this.textContent = textContent;
  }
  _convertMatches(matches, matchesLength) {
    
    if (!matches) {
      return [];
    }
    const { findController, textContentItemsStr } = this;
    let i = 0,
      iIndex = 0;
    const end = textContentItemsStr.length - 1;
    const queryLen = findController.state.query.length;
    const result = [];
    for (let m = 0, mm = matches.length; m < mm; m++) {
      
      let matchIdx = matches[m];
      
      while (i !== end && matchIdx >= iIndex + textContentItemsStr[i].length) {
        iIndex += textContentItemsStr[i].length;
        i++;
      }
      if (i === textContentItemsStr.length) {
        console.error("Could not find a matching mapping");