Add functionality to get full stack trace when exceptions are thrown.

runtime/lib/stacktrace_patch.dart

Index: runtime/lib/stacktrace_patch.dart
===================================================================
--- runtime/lib/stacktrace_patch.dart	(revision 0)
+++ runtime/lib/stacktrace_patch.dart	(revision 0)
@@ -0,0 +1,13 @@
+// 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.
+
+patch class StackTrace {
+  /* patch */ String get fullStackTrace native "Stacktrace_getFullStacktrace";
+
+  /* patch */ String get stackTrace native "Stacktrace_getStacktrace";
+
+  /* patch */ void _setupFullStackTrace()
+      native "Stacktrace_setupFullStacktrace";
+}
+