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
* This method should be called (by the content provider) when elements have
	 * been removed from the model, in order to cause the viewer to accurately
	 * reflect the model. This method only affects the viewer, not the model.
	 * </p>
	 * 
	 * @param elementsOrTreePaths
	 *            the elements to remove
	 */
	public void remove(final Object[] elementsOrTreePaths) {
		assertElementsNotNull(elementsOrTreePaths);
		if (elementsOrTreePaths.length == 0) {
			return;
		}
		preservingSelection(new Runnable() {
			public void run() {
				internalRemove(elementsOrTreePaths);
			}
		});
	}
	/**
	 * Removes the given elements from this viewer whenever they appear as
	 * children of the given parent element. If the given elements also appear
	 * as children of some other parent, the other parent will remain unchanged.
	 * The selection is updated if required.
	 * <p>
	 * This method should be called (by the content provider) when elements have
	 * been removed from the model, in order to cause the viewer to accurately
	 * reflect the model. This method only affects the viewer, not the model.
	 * </p>
	 *