Bug 158778 [Viewers] request for remove(parent, index) API on tree viewer
3.3 It would be helpful to have a 'remove(Object parent, int index)' method on the tree viewer to complement that 'replace(...)' and 'setChildCount(...)' APIs. The debug platform requires such a method to implement filtering in virtual tree views. Rather than performing a 'replace/remove' based on elements, the content provider can make one atomic call to remove an element at a specific index.
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/AbstractTreeViewer.java
*            the element
	 */
	public void remove(Object elementsOrTreePaths) {
		remove(new Object[] { elementsOrTreePaths });
	}
	/**
	 * Removes all items from the given control.
	 * 
	 * @param control
	 *            the control
	 */
	protected abstract void removeAll(Control control);
	/**
	 * Removes a listener for expand and collapse events in this viewer. Has no
	 * affect if an identical listener is not registered.
	 * 
	 * @param listener
	 *            a tree viewer listener
	 */
	public void removeTreeListener(ITreeViewerListener listener) {
		treeListeners.remove(listener);
	}
	/**
	 * This implementation of reveal() reveals the given element or tree path.
	 */
	public void reveal(Object elementOrTreePath) {
		Assert.isNotNull(elementOrTreePath);
		Widget w = internalExpand(elementOrTreePath, true);
		if (w instanceof Item) {
			showItem((Item) w);