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/AbstractTreeViewer.java
if (item instanceof Item) {
			return getExpanded((Item) item);
		}
		return false;
	}
	/**
	 * Returns the number of child items of the given SWT control.
	 * 
	 * @param control
	 *            the control
	 * @return the number of children
	 */
	protected abstract int getItemCount(Control control);
	/**
	 * Returns the number of child items of the given SWT item.
	 * 
	 * @param item
	 *            the item
	 * @return the number of children
	 */
	protected abstract int getItemCount(Item item);
	/**
	 * Returns the child items of the given SWT item.
	 * 
	 * @param item
	 *            the item
	 * @return the child items
	 */
	protected abstract Item[] getItems(Item item);
	/**