Bug 218127 [CommonNavigator] Common Navigator inherited viewer bindings
This enhancement describes the ability for common navigator viewer instances to "inherit" the action and content bindings from other viewers.
bundles/org.eclipse.ui.navigator/src/org/eclipse/ui/internal/navigator/extensions/NavigatorViewerDescriptorManager.java
private static final NavigatorViewerDescriptorManager INSTANCE = new NavigatorViewerDescriptorManager();
	private final Map viewerDescriptors = new HashMap();
	/**
	 * @return The intialized singleton instance of the viewer descriptor
	 *         registry.
	 */
	public static NavigatorViewerDescriptorManager getInstance() {
		return INSTANCE;
	}
	protected NavigatorViewerDescriptorManager() {
		new NavigatorViewerDescriptorRegistry().readRegistry();
	}
	/**
	 * 
	 * @param aViewerId
	 *            The viewer id for the viewer configuration
	 * @return The viewer descriptor for the given viewer id.
	 */