Protocol Buffer runtime library and 'protoc' plugin

lib/protobuf/runtime/ChangeListener.dart

Index: lib/protobuf/runtime/ChangeListener.dart
diff --git a/lib/protobuf/runtime/ChangeListener.dart b/lib/protobuf/runtime/ChangeListener.dart
new file mode 100644
index 0000000000000000000000000000000000000000..30051690e1c6b7098d58e96c58b89248e98d9829
--- /dev/null
+++ b/lib/protobuf/runtime/ChangeListener.dart
@@ -0,0 +1,7 @@
+// Copyright (c) 2011, 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.
+
+interface ChangeListener {
+  void onChanged();
+}