anchor.diff:  
       var args = <String>[];
       if (useDfe) {
  -      args.add('--dfe=utils/kernel-service/kernel-service.dart');
  +      if (!_experimentalStrongMode) {
  +        args.add('--dfe=utils/kernel-service/kernel-service.dart');
  +      }
  +      // TODO(dartbug.com/30480): avoid using additional kernel binaries
         args.add('--kernel-binaries=${buildDir}/patched_sdk');
       }
   
  
positive.code:         alwaysCompile: !_useSdk);
    }
  
    // This step reduces the amount of space needed to run the precompilation
    // tests by 60%.
    Command computeRemoveAssemblyCommand(String tempDir, List arguments,
        Map<String, String> environmentOverrides) {
      var exec = 'rm';
  
negative.code:       args.add('--obfuscate');
      }
  
      if (_experimentalStrongMode) {
        args.add('--experimental-strong-mode');
        args.addAll(arguments.where((name) => !name.endsWith('.dart')));
        args.add(tempKernelFile(tempDir));
      } else {
        args.addAll(arguments);
      }
  
      return Command.compilation('precompiler', tempDir, bootstrapDependencies(),
          exec, args, environmentOverrides,
  