code: function OutlineService(options) {
  		this._serviceRegistry = options.serviceRegistry;
  		this._preferences = options.preferences;
  		EventTarget.attach(this);
  		this._serviceRegistration = this._serviceRegistry.registerService("orion.edit.outline", this); //$NON-NLS-0$
  		this._provider = new Deferred();
  		this._providerResolved = false;
  
  		this.filteredProviders = [];
  		//this.setOutlineProviders(this.filteredProviders);
  	}
docs: Constructs a new outline service. Clients should obtain an outline service by requesting
  the service <code>orion.edit.outline</code> from the service registry. This service constructor
  is only intended to be used by page service registry initialization code.
  @name orion.outliner.OutlineService
  @class <code>OutlineService</code> dispatches an event when an outline for a resource is available.
  Clients may listen to the service's <code>outline</code> event to receive notification when this occurs.
  @param {orion.serviceregistry.ServiceRegistry} options.serviceRegistry The service registry to use for obtaining
  outline providers.
  @param {orion.preferences.PreferencesService} options.preferences The preferences service to use.