anchor.diff:  
   library analyzer_cli.src.bootloader;
   
  +import 'dart:async';
   import 'dart:isolate';
   
   import 'package:analyzer/file_system/physical_file_system.dart';
  
positive.code:   /// (Optional) package map.
    final Map<String, Uri> packages;
  
    /// Args to be passed on to the loaded main.
    final List<String> args;
  
    /// Plugin configuration.
  
negative.code:         packageRootPath != null ? packageRootPath : './packages';
      Uri packageUri = new Uri.file(packageRoot);
  
      Isolate.spawnUri(uri, args, null /* msg */,
          packageRoot: packageUri, onExit: exitListener.sendPort);
  
      return completer.future;
    }
  }
  