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
public boolean isActiveByDefault() {
		if (activeByDefault)
			return true;
		if (initialActivation == null)
			return false;
		IEvaluationContext context = NavigatorPlugin.getEvalContext(new Object());
		return NavigatorPlugin.safeEvaluate(initialActivation, context) == EvaluationResult.TRUE;
	}
	/**
	 * Determine if this content extension would be able to provide children for
	 * the given element.
	 * 
	 * @param anElement
	 *            The element that should be used for the evaluation.
	 * @return True if and only if the extension is enabled for the element.
	 */
	public boolean isTriggerPoint(Object anElement) {
		if (enablement == null || anElement == null) {
			return false;
		}
		IEvaluationContext context = NavigatorPlugin.getEvalContext(anElement);
		return NavigatorPlugin.safeEvaluate(enablement, context) == EvaluationResult.TRUE;
	}
	/**
	 * Determine if this content extension could provide the given element as a
	 * child.
	 * 
	 * <p>
	 * This method is used to determine what the parent of an element could be
	 * for Link with Editor support.