anchor.diff:  import 'package:analyzer/src/summary/api_signature.dart';
   import 'package:analyzer/src/task/api/dart.dart';
   import 'package:analyzer/src/task/api/model.dart';
  -import 'package:analyzer/src/task/dart.dart';
  -import 'package:analyzer/src/task/general.dart';
   import 'package:analyzer/src/task/manager.dart';
  -import 'package:analyzer/src/task/options.dart';
  -import 'package:analyzer/src/task/yaml.dart';
   import 'package:front_end/src/fasta/scanner/token.dart';
   import 'package:path/path.dart' as pathos;
   import 'package:plugin/manager.dart';
  
positive.code:   TaskManager get taskManager {
      if (_taskManager == null) {
        _taskManager = new TaskManager();
        _initializeTaskMap();
        _initializeResults();
      }
      return _taskManager;
    }
  
negative.code:       ExtensionManager manager = new ExtensionManager();
        manager.processPlugins(requiredPlugins);
      }
    }
  
    /**
  