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/NavigatorContentDescriptor.java
private OverridePolicy overridePolicy;
	private String suppressedExtensionId;
	private INavigatorContentDescriptor overriddenDescriptor;
	private int hashCode = HASH_CODE_NOT_COMPUTED;
	private boolean providesSaveables;
	/**
	 * Creates a new content descriptor from a configuration element.
	 * 
	 * @param configElement
	 *            configuration element to create a descriptor from
	 * 
	 * @throws WorkbenchException
	 *             if the configuration element could not be parsed. Reasons
	 *             include:
	 *             <ul>
	 *             <li>A required attribute is missing.</li>
	 *             <li>More elements are define than is allowed.</li>
	 *             </ul>
	 */
	 NavigatorContentDescriptor(IConfigurationElement configElement)
			throws WorkbenchException {
		super();
		this.configElement = configElement;
		init();
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.ui.internal.navigator.extensions.INavigatorContentDescriptor#getId()
	 */