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
}
	/**
	 * 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));
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.jface.viewers.AbstractTreeViewer#internalInitializeTree(org.eclipse.swt.widgets.Control)
	 */
	protected void internalInitializeTree(Control widget) {
		if (getContentProvider() instanceof ILazyTreeContentProvider) {