public void addStyleToDates(String styleName, UTCDate date) {
        styler.setStyleName(date, styleName, true);
        if (isDateVisible(date)) {
            getView().addStyleToDate(styleName, date);
        }
    }
Add a style name to the given dates.
stroom-core-client-widget/src/main/java/stroom/widget/datepicker/client/CustomDatePicker.java