Add renames in output when using the mirror helper library.

sdk/lib/_internal/lib/mirror_helper.dart

Index: sdk/lib/_internal/lib/mirror_helper.dart
diff --git a/sdk/lib/_internal/lib/mirror_helper.dart b/sdk/lib/_internal/lib/mirror_helper.dart
new file mode 100644
index 0000000000000000000000000000000000000000..ea2649ee349c18d63d6a452875e64b1a3b635cb4
--- /dev/null
+++ b/sdk/lib/_internal/lib/mirror_helper.dart
@@ -0,0 +1,25 @@
+// Copyright (c) 2013, 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.
+/**
+ * Helps dealing with reflection in the case that the source code has been
+ * changed as a result of compiling with dart2dart.
+ */
+library _mirror_helper;
+
+import 'dart:mirrors';
+
+/// The compiler will replace this variable with a map containing all the
+/// renames made in dart2dart.
+const Map _SYMBOLS = null;
+
+/// This method is a wrapper for MirrorSystem.getName() and will be inlined and
+/// called in the generated output Dart code.
+String helperGetName(Symbol sym) {
+  var name = MirrorSystem.getName(sym);
+  if (_SYMBOLS.containsKey(name)) {
+    return _SYMBOLS[name].stringValue;
+  } else {
+    return name;
+  }
+}