Provide API support for weak handles and post-mortem finalization.

runtime/vm/dart_api_state.cc

Index: runtime/vm/dart_api_state.cc
diff --git a/runtime/vm/dart_api_state.cc b/runtime/vm/dart_api_state.cc
deleted file mode 100644
index 06ce1fb936165164d6535a18fdf4ae4e7bdd0394..0000000000000000000000000000000000000000
--- a/runtime/vm/dart_api_state.cc
+++ /dev/null
@@ -1,15 +0,0 @@
-// 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.
-
-#include "vm/dart_api_state.h"
-
-namespace dart {
-
-// A distinguished callback which indicates that a persistent handle
-// should not be deleted from the dart api.
-void ProtectedHandleCallback(void* peer) {
-  // Do nothing.
-}
-
-}  // namespace dart