When building standalone Dart executable, put implementation of dart:io natives in a separate libra…

runtime/bin/io_natives.h

Index: runtime/bin/io_natives.h
diff --git a/runtime/vm/random_test.cc b/runtime/bin/io_natives.h
similarity index 50%
copy from runtime/vm/random_test.cc
copy to runtime/bin/io_natives.h
index 2b7f726a218ab971dc80002a419ef74160eda06f..17455552ff5750cc44c93cadb13c97abf7dcbd68 100644
--- a/runtime/vm/random_test.cc
+++ b/runtime/bin/io_natives.h
@@ -2,15 +2,12 @@
 // 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 "platform/assert.h"
-#include "vm/globals.h"
-#include "vm/random.h"
-#include "vm/unit_test.h"
+#ifndef BIN_IO_NATIVES_H_
+#define BIN_IO_NATIVES_H_
 
-namespace dart {
+#include "include/dart_api.h"
 
-TEST_CASE(Random) {
-  EXPECT(Random::RandomInt32() != 0);
-}
+Dart_NativeFunction IONativeLookup(Dart_Handle name,
+                                   int argument_count);
 
-}  // namespace dart
+#endif  // BIN_IO_NATIVES_H_