Bug 214621 [Viewers] Make ComboViewer non-final
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/ComboViewer.java
if (combo == null) {
            ccombo.add(string, index);
        } else {
            combo.add(string, index);
        }
    }
    protected void listSetItem(int index, String string) {
        if (combo == null) {
            ccombo.setItem(index, string);
        } else {
            combo.setItem(index, string);
        }
    }
    protected int[] listGetSelectionIndices() {
        if (combo == null) {
            return new int[] { ccombo.getSelectionIndex() };
        } else {
            return new int[] { combo.getSelectionIndex() };
        }
    }
    protected int listGetItemCount() {
        if (combo == null) {
            return ccombo.getItemCount();
        } else {
            return combo.getItemCount();
        }
    }
    protected void listSetItems(String[] labels) {
        if (combo == null) {
            ccombo.setItems(labels);