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)

const accentGlyphName = StandardEncoding[seac[3]];
        const baseGlyphId = charset.indexOf(baseGlyphName);
        const accentGlyphId = charset.indexOf(accentGlyphName);
        if (baseGlyphId < 0 || accentGlyphId < 0) {
          continue;
        }
        const accentOffset = {
          x: seac[0] * matrix[0] + seac[1] * matrix[2] + matrix[4],
          y: seac[0] * matrix[1] + seac[1] * matrix[3] + matrix[5],
        };
        const charCodes = getCharCodes(mapping, glyphId);
        if (!charCodes) {
          
          
          continue;
        }
        for (let i = 0, ii = charCodes.length; i < ii; i++) {
          const charCode = charCodes[i];
          
          
          const charCodeToGlyphId = newMapping.charCodeToGlyphId;
          const baseFontCharCode = createCharCode(
            charCodeToGlyphId,
            baseGlyphId
          );
          const accentFontCharCode = createCharCode(
            charCodeToGlyphId,
            accentGlyphId
          );
          seacMap[charCode] = {