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/TreeViewer.java
protected void assertContentProviderType(IContentProvider provider) {
		if (provider instanceof ILazyTreeContentProvider) {
			return;
		}
		super.assertContentProviderType(provider);
	}
	protected Object[] getRawChildren(Object parent) {
		if (getContentProvider() instanceof ILazyTreeContentProvider) {
			return new Object[0];
		}
		return super.getRawChildren(parent);
	}
	/**
	 * For a TreeViewer with a tree with the VIRTUAL style bit set, set the
	 * number of children of the given element. To set the number of children of
	 * the invisible root of the tree, the input object is passed as the
	 * element.
	 * 
	 * @param element
	 * @param count
	 * 
	 * <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) {