Bug 154064 Need a way to access the TreeItem or TableItem on a refresh
It is not currently possible to know when an item is refreshed. This is required for ownerDraw support in viewers.
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/TreeViewer.java
* <strong>EXPERIMENTAL</strong>. This class or interface has been added as
	 * part of a work in progress. There is no guarantee that this API will
	 * remain unchanged during the 3.2 release cycle. Please do not use this API
	 * without consulting with the Platform/UI team.
	 * </p>
	 * 
	 * @since 3.2
	 */
	public void setChildCount(Object element, int count) {
		Tree tree = (Tree) doFindInputItem(element);
		if (tree != null) {
			tree.setItemCount(count);
			return;
		}
		Widget[] items = findItems(element);
		for (int i = 0; i < items.length; i++) {
			TreeItem treeItem = (TreeItem) items[i];
			treeItem.setItemCount(count);
		}
	}
	/**
	 * For a TreeViewer with a tree with the VIRTUAL style bit set, replace the
	 * given parent's child at index with the given element. If the given parent
	 * is this viewer's input, this will replace the root element at the given
	 * index.
	 * <p>
	 * This method should be called by implementers of ILazyTreeContentProvider
	 * to populate this viewer.
	 * </p>
	 *