Bug 205049 Other plug-ins should be able to define default content generator
Currently only the content generator can define which plug-ins it can be the default for - we need a way for plug-ins to refer back to the marker support for thier own generator.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/provisional/views/markers/MarkerContentGenerator.java
private Collection filters;
	private IResource[] focusResources = MarkerSupportInternalUtilities.EMPTY_RESOURCE_ARRAY;
	private Collection markerTypes;
	private MarkerField[] visibleFields;
	private IWorkingSet workingSet;
	private boolean andFilters = false;
	private MarkerComparator comparator;
	private IMemento memento;
	/**
	 * Create a new MarkerContentGenerator
	 * 
	 * @param element
	 */
	public MarkerContentGenerator(IConfigurationElement element) {
		configurationElement = element;
	}
	/**
	 * Add the resources in resourceMapping to the resourceCollection
	 * 
	 * @param resourceCollection
	 * @param resourceMapping
	 */
	private void addResources(Collection resourceCollection,
			ResourceMapping resourceMapping) {
		try {
			ResourceTraversal[] traversals = resourceMapping.getTraversals(
					ResourceMappingContext.LOCAL_CONTEXT,
					new NullProgressMonitor());
			for (int i = 0; i < traversals.length; i++) {
				ResourceTraversal traversal = traversals[i];