anchor.diff:    AceManager(this.parentElement,
                this.delegate,
                svc.Services services,
  -             this._prefs) {
  +             PreferenceStore prefs) {
       ace.implementation = ACE_PROXY_IMPLEMENTATION;
       _aceEditor = ace.edit(parentElement);
       _aceEditor.renderer.fixedWidthGutter = true;
  
positive.code:     ace.Mode.extensionMap['lock'] = ace.Mode.YAML;
      ace.Mode.extensionMap['project'] = ace.Mode.XML;
  
      outline = new Outline(services, parentElement, _prefs);
      outline.onChildSelected.listen((OutlineItem item) {
        ace.Point startPoint =
            currentSession.document.indexToPosition(item.startOffset);
  
negative.code:   Outline outline;
  
    ace.Editor _aceEditor;
  
    workspace.Marker _currentMarker;
  
  