Bug 275929 [CommonNavigator] IPipelinedTreeContentProvider.getPipelinedElements() not ever called
bundles/org.eclipse.ui.navigator/src/org/eclipse/ui/internal/navigator/NavigatorContentServiceContentProvider.java
/**
	 * Query each of <code>theOverridingExtensions</code> for elements, and
	 * then pipe them through the Pipeline content provider.
	 * 
	 * @param anInputElement
	 *            The input element in the tree
	 * @param theOverridingExtensions
	 *            The set of overriding extensions that should participate in
	 *            the pipeline chain
	 * @param theCurrentParent
	 *            The current elements to return to the viewer (should be
	 *            modifiable)
	 * @return The set of elements to return to the viewer
	 */
	private Object pipelineParent(Object anInputElement,
			NavigatorContentExtension[] theOverridingExtensions,
			Object theCurrentParent) {
		IPipelinedTreeContentProvider pipelinedContentProvider;
		NavigatorContentExtension[] overridingExtensions;
		Object aSuggestedParent = null;
		for (int i = 0; i < theOverridingExtensions.length; i++) {
			if (theOverridingExtensions[i].getContentProvider() instanceof IPipelinedTreeContentProvider) {
				pipelinedContentProvider = (IPipelinedTreeContentProvider) theOverridingExtensions[i]
						.getContentProvider();
				aSuggestedParent = pipelinedContentProvider.getPipelinedParent(
						anInputElement, aSuggestedParent);
				overridingExtensions = theOverridingExtensions[i]
						.getOverridingExtensionsForTriggerPoint(anInputElement);
				if (overridingExtensions.length > 0) {
					aSuggestedParent = pipelineParent(anInputElement,