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)

correctlySorted = false;
            }
          }
          if (correctlySorted) {
            canBreak = true;
          }
        }
        if (useTable) {
          potentialTable = {
            platformId,
            encodingId,
            offset,
          };
        }
        if (canBreak) {
          break;
        }
      }
      if (potentialTable) {
        file.pos = start + potentialTable.offset;
      }
      if (!potentialTable || file.peekByte() === -1) {
        warn("Could not find a preferred cmap table.");
        return {
          platformId: -1,
          encodingId: -1,
          mappings: [],
          hasShortCmap: false,
        };
      }