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)

if (!properties.fontMatrix) {
    return;
  }
  if (properties.fontMatrix[0] === FONT_IDENTITY_MATRIX[0]) {
    return;
  }
  
  const scale = 0.001 / properties.fontMatrix[0];
  const glyphsWidths = properties.widths;
  for (const glyph in glyphsWidths) {
    glyphsWidths[glyph] *= scale;
  }
  properties.defaultWidth *= scale;
}
function adjustToUnicode(properties, builtInEncoding) {