Bug 153993 [Viewers] Common Baseclass for Tree/TableEditorImpl
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/ColumnViewer.java
* Get the ViewerRow associated with the Widget.
	 * 
	 * @param item
	 * @return ViewerRow
	 */
	protected ViewerRow getViewerRowFromItem(Widget item) {
		return (ViewerRow) item.getData(ViewerRow.ROWPART_KEY);
	}
	/**
	 * Get the widget for the column at columnIndex.
	 * 
	 * @param columnIndex
	 * @return Widget
	 */
	protected abstract Widget getColumnViewerOwner(int columnIndex);
	/**
	 * Returns the cell modifier of this viewer.
	 * 
	 * @return the cell modifier
	 * @since 3.1 (in subclasses, added in 3.3 to abstract class)
	 */
	public abstract ICellModifier getCellModifier();
	/**
	 * Return the CellEditors for the receiver.
	 * 
	 * @return CellEditor[]
	 * @since 3.1 (in subclasses, added in 3.3 to abstract class)
	 */
	public abstract CellEditor[] getCellEditors();
	/**