Bug 184755 [DataBinding] internal tree content provider does not work
I broke the tree content providers while trying to update them to use TreePaths. It would be good to have a working implementation again...
bundles/org.eclipse.jface.databinding/src/org/eclipse/jface/internal/databinding/internal/viewers/UnorderedTreeNode.java
* 
     * @return a parent node, or null
     */
    public Object getParent() {
        return parent;
    }
    
    /**
     * @return the set of known parent nodes
     */
    public Set getParents() {
        if (parents == null) {
            if (parent == null) {
                return Collections.EMPTY_SET;
            }
			return Collections.singleton(parent);
        }
		return parents;
    }
    
    /**
     * Called when the child set changes. Should not be called directly by the viewer.
     */
    public void handleSetChange(SetChangeEvent event) {
        boolean shouldHavePendingNode = children.isEmpty() && children.isStale();
        
        Set additions = event.diff.getAdditions();
        
        if (shouldHavePendingNode && !hasPendingNode) {
            HashSet newAdditions = new HashSet();