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

vm/native_entry_test.h

Index: vm/native_entry_test.h
===================================================================
--- vm/native_entry_test.h	(revision 11528)
+++ vm/native_entry_test.h	(working copy)
@@ -5,24 +5,14 @@
 #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;
+void TestSmiSub(Dart_NativeArguments args);
+void TestSmiSum(Dart_NativeArguments args);
+void TestStaticCallPatching(Dart_NativeArguments args);
 
-
-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);
-
 }  // namespace dart
 
 #endif  // VM_NATIVE_ENTRY_TEST_H_