anchor.diff:     */
     AnalysisContext _context;
   
  -  PubFolder(DartSdk sdk, this._folder, this._pubspecFile) {
  +  ContextDirectory(DartSdk sdk, this._folder, this._pubspecFile) {
       // create AnalysisContext
       _context = AnalysisEngine.instance.createAnalysisContext();
       // TODO(scheglov) replace FileUriResolver with an Resource based resolver
  
positive.code:   DartSdk defaultSdk = SHARED_SDK;
  
    /**
     * A table mapping [Folder]s to the [PubFolder]s associated with them.
     */
    final Map<Folder, PubFolder> folderMap = <Folder, PubFolder>{};
  
    /**
     * The context identifier used in the last status notification.
  
negative.code: 
  
  /**
   * Instances of [ContextDirectory] represents a [Folder] associated with an
   * analysis context.  The folder may or may not contain a Pub `pubspec.yaml`.
   *
   * TODO(scheglov) implement complete projects/contexts semantics.
   *
   * This class is intentionally simplified to serve as a base to start working
   * on services while work on complete semantics is being done in parallel.
   */
  class ContextDirectory {
    /**
     * The root [Folder] of this [ContextDirectory].
     */
    final Folder _folder;
  
  