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/NavigatorPipelineService.java
private NavigatorContentService contentService;
	/**
	 * Create a pipeline assistant for the given content service.
	 * 
	 * @param aContentService
	 *            The content service that will drive this pipeline assistant.
	 */
	public NavigatorPipelineService(NavigatorContentService aContentService) {
		contentService = aContentService;
	}
	/**
	 * Intercept attempts to add elements directly to the viewer.
	 * 
	 * <p>
	 * For content extensions that reshape the structure of children in a
	 * viewer, their overridden extensions may sometimes use optimized refreshes
	 * to add elements to the tree. These attempts must be intercepted and
	 * mapped to the correct set of model elements in the overriding extension.
	 * Clients may add, remove, or modify elements in the given set of added
	 * children. Clients should return a set for downstream extensions to
	 * massage further.