Add WATCHLISTS file.

WATCHLISTS

Index: WATCHLISTS
===================================================================
--- WATCHLISTS	(revision 0)
+++ WATCHLISTS	(revision 0)
@@ -0,0 +1,19 @@
+# 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.
+
+# Watchlist Rules
+# Refer: http://dev.chromium.org/developers/contributing-code/watchlists
+
+{
+  'WATCHLIST_DEFINITIONS': {
+    'runtime': {
+      'filepath': 'runtime/',
+    },
+  },
+
+  'WATCHLISTS': {
+    'runtime': ['vm-dev@dartlang.org'],
+  },
+}
+