Viewer:  https://mozilla.github.io/pdf.js/web/viewer.html
Chrome on Windows 10
When the attached PDF file is viewed, some of the fonts display as garbled text. 
[Arial, Courier, Times New Roman]
The file views correctly in Adobe Reader.
[fff.pdf](https://github.com/mozilla/pdf.js/files/4652174/fff.pdf)

constructor(
    originalCharCode,
    fontChar,
    unicode,
    accent,
    width,
    vmetric,
    operatorListId,
    isSpace,
    isInFont
  ) {
    this.originalCharCode = originalCharCode;
    this.fontChar = fontChar;
    this.unicode = unicode;
    this.accent = accent;
    this.width = width;
    this.vmetric = vmetric;
    this.operatorListId = operatorListId;
    this.isSpace = isSpace;
    this.isInFont = isInFont;
  }
  matchesForCache(