Fix bug with CHA dependencies by recording a set of classes for registering code.

tests/language/cha_deopt1_deferred_lib.dart

Index: tests/language/cha_deopt1_deferred_lib.dart
===================================================================
--- tests/language/cha_deopt1_deferred_lib.dart	(revision 0)
+++ tests/language/cha_deopt1_deferred_lib.dart	(revision 0)
@@ -0,0 +1,13 @@
+// Copyright (c) 2014, 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 "cha_deopt1_lib.dart";
+
+class U extends T {
+
+  m() => "good horse";
+
+}
+
+make_u() => new U();