public static <T_ROW> ColumnBuilder<T_ROW, String, ColourSwatchCell> colourSwatchColumnBuilder(
            final Function<T_ROW, String> cssColourExtractor) {
        return new ColumnBuilder<T_ROW, String, ColourSwatchCell>(cssColourExtractor, ColourSwatchCell::new);
    }
A simple text cell with the value of the hover tooltip provided by tooltipFunction, which is
applied to the cell value.
stroom-core-client/src/main/java/stroom/util/client/DataGridUtil.java