Support (de)serialization from command-line

tests/compiler/dart2js/serialization/test_helper.dart

 // Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library dart2js.serialization_test_helper;
 
-import 'dart:io';
-import '../memory_compiler.dart';
-import 'package:async_helper/async_helper.dart';
 import 'package:compiler/src/common/resolution.dart';
-import 'package:compiler/src/commandline_options.dart';
-import 'package:compiler/src/constants/constructors.dart';
 import 'package:compiler/src/constants/expressions.dart';
 import 'package:compiler/src/dart_types.dart';
 import 'package:compiler/src/compiler.dart';
-import 'package:compiler/src/diagnostics/invariant.dart';
 import 'package:compiler/src/elements/elements.dart';
-import 'package:compiler/src/elements/visitor.dart';
-import 'package:compiler/src/ordered_typeset.dart';
-import 'package:compiler/src/serialization/element_serialization.dart';
 import 'package:compiler/src/serialization/equivalence.dart';
-import 'package:compiler/src/serialization/json_serializer.dart';
-import 'package:compiler/src/serialization/serialization.dart';
 import 'package:compiler/src/tree/nodes.dart';
 
 /// Strategy for checking equivalence.
 ///
 /// Use this strategy to fail early with contextual information in the event of
 /// inequivalence.
 class CheckStrategy implements TestStrategy {
   const CheckStrategy();
 
   @override
@@ skipping 352 matching lines @@
 
   if (impact1 == null) {
     throw 'Missing impact for $member1. $member2 has $impact2';
   }
   if (impact2 == null) {
     throw 'Missing impact for $member2. $member1 has $impact1';
   }
 
   testResolutionImpactEquivalence(impact1, impact2, const CheckStrategy());
 }