Add a platform plugin infrastructure.

test/utils.dart

 // Copyright (c) 2015, 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.
 
 import 'dart:async';
 import 'dart:collection';
 
 import 'package:test/src/backend/declarer.dart';
 import 'package:test/src/backend/group.dart';
 import 'package:test/src/backend/group_entry.dart';
 import 'package:test/src/backend/invoker.dart';
 import 'package:test/src/backend/live_test.dart';
 import 'package:test/src/backend/metadata.dart';
 import 'package:test/src/backend/state.dart';
 import 'package:test/src/backend/suite.dart';
 import 'package:test/src/runner/application_exception.dart';
 import 'package:test/src/runner/engine.dart';
 import 'package:test/src/runner/load_exception.dart';
+import 'package:test/src/runner/plugin/environment.dart';
 import 'package:test/src/runner/runner_suite.dart';
-import 'package:test/src/runner/vm/environment.dart';
 import 'package:test/src/util/remote_exception.dart';
 import 'package:test/test.dart';
 
 /// The string representation of an untyped closure with no arguments.
 ///
 /// This differs between dart2js and the VM.
 final String closureString = (() {}).toString();
 
 // The last state change detected via [expectStates].
 State lastState;
@@ skipping 270 matching lines @@
 /// Runs [body] with a declarer and returns the declared entries.
 List<GroupEntry> declare(void body()) {
   var declarer = new Declarer()..declare(body);
   return declarer.build().entries;
 }
 
 /// Runs [body] with a declarer and returns an engine that runs those tests.
 Engine declareEngine(void body()) {
   var declarer = new Declarer()..declare(body);
   return new Engine.withSuites([
-    new RunnerSuite(const VMEnvironment(), declarer.build())
+    new RunnerSuite(const PluginEnvironment(), declarer.build())
   ]);
 }