Puzzled why fontSize and fontName are treated explicitelty here, instead of in StyleSummary. Needs a comment why.

Also please align the naming of fontSizeValue and fontNameValue with selectionStylesSummary selectionAppliedStyles, to make clear they all serve the same purpose. 
cachedStylesSummary, cachedStyles, cachedFontSizeValue, cachedFontNameValue?
and updateSelectionStylesInfo -> updateCache?