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)

return Object.values(this._glyphCache);
  }
  /**
   * Encode a js string using font encoding.
   * The resulting array contains an encoded string at even positions
   * (can be empty) and a non-encoded one at odd positions.
   * @param {String} a js string.
   * @returns {Array<String>} an array of encoded strings or non-encoded ones.
   */
  encodeString(str) {
    const buffers = [];
    const currentBuf = [];
    
    
    
    
    const hasCurrentBufErrors = () => buffers.length % 2 === 1;
    const getCharCode =
      this.toUnicode instanceof IdentityToUnicodeMap
        ? unicode => this.toUnicode.charCodeOf(unicode)
        : unicode => this.toUnicode.charCodeOf(String.fromCodePoint(unicode));
    for (let i = 0, ii = str.length; i < ii; i++) {
      const unicode = str.codePointAt(i);
      if (unicode > 0xd7ff && (unicode < 0xe000 || unicode > 0xfffd)) {