Move package:testing to SDK.

pkg/testing/lib/testing.dart

Index: pkg/testing/lib/testing.dart
diff --git a/pkg/testing/lib/testing.dart b/pkg/testing/lib/testing.dart
new file mode 100644
index 0000000000000000000000000000000000000000..25dd5e09a4b827d13482dfb0f60326637014880b
--- /dev/null
+++ b/pkg/testing/lib/testing.dart
@@ -0,0 +1,25 @@
+// 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.md file.
+
+library testing;
+
+export 'dart:async' show
+    Future;
+
+export 'src/discover.dart';
+
+export 'src/test_description.dart';
+
+export 'src/chain.dart' show
+    Chain,
+    ChainContext,
+    Result,
+    Step;
+
+export 'src/stdio_process.dart' show
+    StdioProcess;
+
+export 'src/run.dart' show
+    run,
+    runMe;