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)

fileType = "TrueType";
    }
  } else if (isOpenTypeFile(file)) {
    if (composite) {
      fileType = "CIDFontType2";
    } else {
      fileType = "OpenType";
    }
  } else if (isType1File(file)) {
    if (composite) {
      fileType = "CIDFontType0";
    } else {
      fileType = type === "MMType1" ? "MMType1" : "Type1";
    }
  } else if (isCFFFile(file)) {
    if (composite) {
      fileType = "CIDFontType0";
      fileSubtype = "CIDFontType0C";
    } else {
      fileType = type === "MMType1" ? "MMType1" : "Type1";
      fileSubtype = "Type1C";
    }
  } else {
    warn("getFontFileType: Unable to detect correct font file Type/Subtype.");
    fileType = type;
    fileSubtype = subtype;
  }
  return [fileType, fileSubtype];
}
function buildToFontChar(encoding, glyphsUnicodeMap, differences) {