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
return EMPTY_RESOURCE_ARRAY;
		HashSet projects = new HashSet();
		for (int idx = 0; idx < focusResources.length; idx++) {
			projects.add(focusResources[idx].getProject());
		}
		if (projects.isEmpty())
			return EMPTY_RESOURCE_ARRAY;
		return (IResource[]) projects.toArray(new IResource[projects.size()]);
	}
	/**
	 * Get the resources in the current working set.
	 * 
	 * @return IResource[]
	 */
	private IResource[] getResourcesInWorkingSet() {
		
		if (workingSet == null) {
			return new IResource[0];
		}
		if (workingSet.isEmpty()) {
			return new IResource[] { ResourcesPlugin.getWorkspace().getRoot() };
		}
		IAdaptable[] elements = workingSet.getElements();
		List result = new ArrayList(elements.length);
		for (int idx = 0; idx < elements.length; idx++) {
			IResource next = (IResource) elements[idx]
					.getAdapter(IResource.class);
			if (next != null) {
				result.add(next);
			}