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)

info(
          "Attempting to fix invalid indexToLocFormat in head table: " +
            indexToLocFormat
        );
        
        
        
        
        
        
        
        
        
        const numGlyphsPlusOne = numGlyphs + 1;
        if (locaLength === numGlyphsPlusOne << 1) {
          
          data[50] = 0;
          data[51] = 0;
        } else if (locaLength === numGlyphsPlusOne << 2) {
          
          data[50] = 0;
          data[51] = 1;
        } else {
          throw new FormatError(
            "Could not fix indexToLocFormat: " + indexToLocFormat
          );
        }
      }
    }
    function sanitizeGlyphLocations(