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)

warn("cmap table has unsupported format: " + format);
        return {
          platformId: -1,
          encodingId: -1,
          mappings: [],
          hasShortCmap: false,
        };
      }
      
      mappings.sort(function (a, b) {
        return a.charCode - b.charCode;
      });
      for (let i = 1; i < mappings.length; i++) {
        if (mappings[i - 1].charCode === mappings[i].charCode) {
          mappings.splice(i, 1);
          i--;
        }
      }
      return {
        platformId: potentialTable.platformId,
        encodingId: potentialTable.encodingId,
        mappings,
        hasShortCmap,
      };
    }
    function sanitizeMetrics(
      file,
      header,
      metrics,
      headTable,