Use the return value of vm native methods to set the return value,

vm/native_entry_test.h

 // 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.
 
 #ifndef VM_NATIVE_ENTRY_TEST_H_
 #define VM_NATIVE_ENTRY_TEST_H_
 
-#include "vm/native_entry.h"
-
 #include "include/dart_api.h"
 
 namespace dart {
 
-// Forward declarations.
-class String;
-
-
-DECLARE_NATIVE_ENTRY(TestSmiSub, 2);
-DECLARE_NATIVE_ENTRY(TestSmiSum, 6);
-DECLARE_NATIVE_ENTRY(TestStaticCallPatching, 0);
-
-// Helper function for looking up native test functions.
-extern Dart_NativeFunction NativeTestEntry_Lookup(const String& name,
-                                                  int argument_count);
+void TestSmiSub(Dart_NativeArguments args);
+void TestSmiSum(Dart_NativeArguments args);
+void TestStaticCallPatching(Dart_NativeArguments args);
 
 }  // namespace dart
 
 #endif  // VM_NATIVE_ENTRY_TEST_H_