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/NavigatorContentService.java
synchronized (this) {
			if (descriptionProvider == null) {
				descriptionProvider = new NavigatorContentServiceDescriptionProvider(
						this);
			}
		}
		return descriptionProvider;
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.ui.internal.navigator.INavigatorContentService#dispose()
	 */
	public void dispose() {
		if (navigatorSaveablesService != null) {
			assistant.removeListener(navigatorSaveablesService);
		}
		if (navigatorSorterService != null) {
			assistant.removeListener(navigatorSorterService);
		}
		synchronized (this) {
			for (Iterator contentItr = contentExtensions.values().iterator(); contentItr
					.hasNext();) {
				((NavigatorContentExtension) contentItr.next()).dispose();
			}
		}
		getActivationService().removeExtensionActivationListener(this);
		assistant.dispose();
		isDisposed = true;
	}