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)

safeString16(properties.ascent) + 
        string16(properties.italicAngle ? 2 : 0) + 
        "\x00\x11" + 
        "\x00\x00" + 
        "\x00\x00" + 
        "\x00\x00"
    ); 
    
    builder.addTable(
      "hhea",
      "\x00\x01\x00\x00" + 
        safeString16(properties.ascent) + 
        safeString16(properties.descent) + 
        "\x00\x00" + 
        "\xFF\xFF" + 
        "\x00\x00" + 
        "\x00\x00" + 
        "\x00\x00" + 
        safeString16(properties.capHeight) + 
        safeString16(Math.tan(properties.italicAngle) * properties.xHeight) + 
        "\x00\x00" + 
        "\x00\x00" + 
        "\x00\x00" + 
        "\x00\x00" + 
        "\x00\x00" + 
        "\x00\x00" + 
        string16(numGlyphs)
    ); 
    
    builder.addTable(