Bug 174701 [Viewers] ViewerRow should be reused instead of connected to the Item
Currently we create a ViewerRow ver every Item we create this can degrade performance, we should cache the row and reuse it
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/ColumnViewer.java
*/
	ViewerCell getCell(Point point) {
		ViewerRow row = getViewerRow(point);
		if (row != null) {
			return row.getCell(point);
		}
		return null;
	}
	/**
	 * Returns the viewer row at the given widget-relative coordinates.
	 * 
	 * @param point
	 *            the widget-relative coordinates of the viewer row
	 * @return ViewerRow the row or <code>null</code> if no row is found at
	 *         the given coordinates
	 */
	protected ViewerRow getViewerRow(Point point) {
		Item item = getItemAt(point);
		if (item != null) {
			return getViewerRowFromItem(item);
		}
		return null;
	}
	/**
	 * Returns the viewer row associated with the given row widget.
	 * 
	 * @param item
	 *            the row widget
	 * @return ViewerRow the associated viewer row
	 */