Bug 139986 [CommonNavigator] Convert catch(Error/Throwable) to SafeRunner
In several places the CN framework uses catch(Error/Throwable) to ensure that code does not bring the framework down. Change these to use SafeRunner.
bundles/org.eclipse.ui.navigator/src/org/eclipse/ui/internal/navigator/extensions/NavigatorContentExtension.java
private StructuredViewerManager viewerManager;
	/**
	 * Create an object to manage the instantiated elements from the extension.
	 * 
	 * @param aDescriptor
	 *            The descriptor that knows how to create elements and knows the
	 *            id of the extension
	 * @param aContentService
	 *            The content service that will manage this extension
	 * @param aViewerManager
	 *            The viewer manager that knows how to initialize the content
	 *            provider created by this extension.
	 */
	public NavigatorContentExtension(NavigatorContentDescriptor aDescriptor,
			NavigatorContentService aContentService,
			StructuredViewerManager aViewerManager) {
		super();
		Assert.isNotNull(aDescriptor);
		descriptor = aDescriptor;
		contentService = aContentService;
		viewerManager = aViewerManager;
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.eclipse.ui.internal.navigator.extensions.INavigatorContentExtension
	 * #getId()
	 */
	public String getId() {