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
if( part == null ) {
			part = new TreeViewerRow(((TreeItem)item));
		}
		
		return part;
	}
		
	/**
	 * Create a new ViewerRow at rowIndex
	 * @param parent
	 * @param style
	 * @param rowIndex
	 * @return ViewerRow
	 */
	private ViewerRow createNewRowPart(ViewerRow parent, int style, int rowIndex) {
		if( parent == null ) {
			if( rowIndex >= 0 ) {
				return getRowPartFromItem(new TreeItem(tree,style,rowIndex));
			}
			return getRowPartFromItem(new TreeItem(tree,style));
		}
		
		if( rowIndex >= 0 ) {
			return getRowPartFromItem(new TreeItem((TreeItem)parent.getItem(),SWT.NONE,rowIndex));
		}
		
		return getRowPartFromItem(new TreeItem((TreeItem)parent.getItem(),SWT.NONE));
	}
}