Bug 89606 [Viewers] Remove protected API added to support prototype of grouping by working sets
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/AbstractTreeViewer.java
/*
	 * (non-Javadoc)
	 *
	 * @see org.eclipse.jface.viewers.ColumnViewer#getColumnViewerOwner(int)
	 */
	protected Widget getColumnViewerOwner(int columnIndex) {
		
		return null;
	}
	/**
	 * This implementation of {@link #getItemAt(Point)} returns null to ensure
	 * API backwards compatibility. Subclasses should override.
	 *
	 * @since 3.3
	 */
	protected Item getItemAt(Point point) {
		return null;
	}
	/**
	 * This implementation of {@link #createViewerEditor()} returns null to ensure
	 * API backwards compatibility. Subclasses should override.
	 *
	 * @since 3.3
	 */
	protected ColumnViewerEditor createViewerEditor() {
		return null;
	}
	/**
	 * Returns the number of columns of this viewer.
	 * <p><b>Subclasses should overwrite this method, which has a default