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/ViewerRow.java
* 
	 * @see #getNeighbor(int, boolean)
	 */
	public static final int ABOVE = 1;
	/**
	 * Constant denoting the row below the current one (value is 2).
	 * 
	 * @see #getNeighbor(int, boolean)
	 */
	public static final int BELOW = 2;
	/**
	 * Create a new instance of the receiver.
	 * 
	 * @param item
	 */
	protected ViewerRow(final Item item) {
		item.setData(ViewerRow.ROWPART_KEY, this);
	}
	/**
	 * Get the bounds of the entry at the columnIndex,
	 * 
	 * @param columnIndex
	 * @return {@link Rectangle}
	 */
	public abstract Rectangle getBounds(int columnIndex);
	/**
	 * Return the bounds for the whole item.
	 * 
	 * @return {@link Rectangle}
	 */