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/NavigatorContentDescriptorManager.java
}
		cache.setDescriptors(anElement, (NavigatorContentDescriptor[]) descriptors.toArray(new NavigatorContentDescriptor[descriptors.size()]));
		return descriptors;
	}
	private EvaluationCache getEvaluationCache(Map anEvaluationMap,
			VisibilityAssistant aVisibilityAssistant) {
		EvaluationCache c = (EvaluationCache) anEvaluationMap
				.get(aVisibilityAssistant);
		if (c == null) {
			anEvaluationMap.put(aVisibilityAssistant, c = new EvaluationCache(
					aVisibilityAssistant));
		}
		return c;
	}
	private boolean addDescriptorsConsideringOverrides(Object anElement,
			Set theChildDescriptors, VisibilityAssistant aVisibilityAssistant,
			Set theFoundDescriptors, boolean possibleChild) {
		int initialSize = theFoundDescriptors.size();
		NavigatorContentDescriptor descriptor;
		
		for (Iterator contentDescriptorsItr = theChildDescriptors.iterator(); contentDescriptorsItr
				.hasNext();) {
			descriptor = (NavigatorContentDescriptor) contentDescriptorsItr
					.next();
			boolean isApplicable = aVisibilityAssistant.isActive(descriptor)
					&& aVisibilityAssistant.isVisible(descriptor)
					&& (possibleChild ? descriptor.isPossibleChild(anElement) : descriptor.isTriggerPoint(anElement));
			if (descriptor.hasOverridingExtensions()) {
				boolean isOverridden;
				Set overridingDescriptors = new TreeSet(ExtensionSequenceNumberComparator.INSTANCE);