Refactor CompilerOutput

tests/compiler/dart2js/dump_info_test.dart

 // Copyright (c) 2012, 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.
 // Test that parameters keep their names in the output.
 
 import 'dart:convert';
 import 'package:expect/expect.dart';
 import 'package:async_helper/async_helper.dart';
 import 'memory_compiler.dart';
 
@@ skipping 80 matching lines @@
 const String TEST_INLINED_2 = r"""
   funcA() => funcB();
   funcB() => print("hello");
    main() => funcA();
 """;
 
 typedef void JsonTaking(Map<String, dynamic> json);
 
 jsonTest(String program, JsonTaking testFn) async {
   var result = await runCompiler(
-      memorySourceFiles: {'main.dart': program}, options: ['--dump-info']);
+      memorySourceFiles: {'main.dart': program},
+      options: ['--out=out.js', '--dump-info']);
   var compiler = result.compiler;
   Expect.isFalse(compiler.compilationFailed);
   var dumpTask = compiler.dumpInfoTask;
 
   StringBuffer sb = new StringBuffer();
   dumpTask.dumpInfoJson(
       sb, compiler.resolutionWorldBuilder.closedWorldForTesting);
   String json = sb.toString();
   Map<String, dynamic> map = JSON.decode(json);
 
@@ skipping 61 matching lines @@
     Expect.isTrue(main_ != null);
     Expect.isTrue(fn1 != null);
     Expect.isTrue(fn2 != null);
     Expect.isTrue(deps.containsKey(main_['id']));
     Expect.isTrue(deps.containsKey(fn1['id']));
     Expect.isTrue(deps.containsKey(fn2['id']));
     Expect.isTrue(deps[main_['id']].any((dep) => dep['id'] == fn1['id']));
     Expect.isTrue(deps[fn1['id']].any((dep) => dep['id'] == fn2['id']));
   });
 }