Make Dart_IdentityEqual live up to its spec and not leak boxing implementation detail.

runtime/lib/identical.h

Index: runtime/lib/identical.h
diff --git a/runtime/bin/vmservice.h b/runtime/lib/identical.h
similarity index 58%
copy from runtime/bin/vmservice.h
copy to runtime/lib/identical.h
index 4dcf93f704aaf7e82fc4d54ab5dbd81d2c7ee64e..b0e0a3c87c3f7d446b7a2ca838e6a35c37da4609 100644
--- a/runtime/bin/vmservice.h
+++ b/runtime/lib/identical.h
@@ -2,16 +2,16 @@
 // 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.
 
-#ifndef BIN_VMSERVICE_H_
-#define BIN_VMSERVICE_H_
+#ifndef LIB_IDENTICAL_H_
+#define LIB_IDENTICAL_H_
 
-#include "include/dart_api.h"
+#include "vm/allocation.h"
+#include "vm/object.h"
 
 namespace dart {
-namespace bin {
 
+RawBool* Identical(const Instance& a, const Instance& b);
 
-}  // namespace bin
 }  // namespace dart
 
-#endif  // BIN_VMSERVICE_H_
+#endif  // LIB_IDENTICAL_H_