anchor.diff:                    .resolve('dart-sdk/bin/snapshots/dart2js.dart.snapshot')
               ]);
     }
  -}
  -
  -/// Configuration for dart2js.
  -class Dart2jsCompilerConfiguration extends Dart2xCompilerConfiguration {
  -  Dart2jsCompilerConfiguration(TestConfiguration configuration)
  -      : super('dart2js', configuration);
   
     List<String> computeCompilerArguments(
         TestFile testFile, List<String> vmOptions, List<String> args) {
  
positive.code:   }
  }
  
  /// Common configuration for dart2js-based tools, such as dart2js.
  class Dart2xCompilerConfiguration extends CompilerConfiguration {
    static final Map<String, List<Uri>> _bootstrapDependenciesCache = {};
  
    final String moniker;
  
    Dart2xCompilerConfiguration(this.moniker, TestConfiguration configuration)
        : super._subclass(configuration);
  
    String computeCompilerPath() {
  
negative.code:     arguments = arguments.toList();
      arguments.add('--out=$outputFileName');
  
      return CompilationCommand(
          'dart2js',
          outputFileName,
          bootstrapDependencies(),
          computeCompilerPath(),
          arguments,
          environmentOverrides,
          alwaysCompile: !_useSdk);
    }
  
  