Add a unit test Benchmark_UseDartApi to measure dart api overhead.

runtime/vm/dart_api_impl.cc

 // Copyright (c) 2012, 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 "include/dart_api.h"
 
 #include "vm/bigint_operations.h"
 #include "vm/class_finalizer.h"
 #include "vm/compiler.h"
 #include "vm/dart.h"
@@ skipping 2901 matching lines @@
 }
 
 
 // --- Native functions ---
 
 
 DART_EXPORT Dart_Handle Dart_GetNativeArgument(Dart_NativeArguments args,
                                                int index) {
   DARTSCOPE(Isolate::Current());
   NativeArguments* arguments = reinterpret_cast<NativeArguments*>(args);
+  if (index < 0 || index >= arguments->Count()) {
+    return Api::NewError(
+        "%s: argument 'index' out of range. Expected 0..%d but saw %d.",
+        CURRENT_FUNC, arguments->Count() - 1, index);
+  }
   const Object& obj = Object::Handle(arguments->At(index));
   return Api::NewLocalHandle(obj);
 }
 
 
 DART_EXPORT int Dart_GetNativeArgumentCount(Dart_NativeArguments args) {
   CHECK_ISOLATE(Isolate::Current());
   NativeArguments* arguments = reinterpret_cast<NativeArguments*>(args);
   return arguments->Count();
 }
@@ skipping 326 matching lines @@
       *buffer = NULL;
     }
     delete debug_region;
   } else {
     *buffer = NULL;
     *buffer_size = 0;
   }
 }
 
 }  // namespace dart