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
* @param item
	 *            the SWT item
	 * @param element
	 *            the element
	 */
	protected void doUpdateItem(final Item item, Object element) {
		if (item.isDisposed()) {
			unmapElement(element, item);
			return;
		}
		int columnCount = doGetColumnCount();
		if (columnCount == 0)
			columnCount = 1;
		for (int column = 0; column < columnCount; column++) {
			ViewerColumn columnViewer = getViewerColumn(column);
			columnViewer.refresh(updateCell(getViewerRowFromItem(item),
					column));
			
			
			if (item.isDisposed()) {
				unmapElement(element, item);
				return;
			}
		}
	}
	
	/**
	 * Returns <code>true</code> if the given list and array of items refer to
	 * the same model elements. Order is unimportant.
	 * <p>