Fix native argument handling

runtime/vm/exceptions_test.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 "platform/assert.h"
 #include "vm/dart_api_impl.h"
 #include "vm/unit_test.h"
 
 namespace dart {
 
 // Only ia32 and x64 can run execution tests.
 #if defined(TARGET_ARCH_IA32) || defined(TARGET_ARCH_X64)
 #define FUNCTION_NAME(name) UnhandledExcp_##name
 #define REGISTER_FUNCTION(name, count)                                         \
   { ""#name, FUNCTION_NAME(name), count },
 
 
 void FUNCTION_NAME(Unhandled_equals)(Dart_NativeArguments args) {
   NativeArguments* arguments = reinterpret_cast<NativeArguments*>(args);
-  const Instance& expected = Instance::CheckedHandle(arguments->At(0));
-  const Instance& actual = Instance::CheckedHandle(arguments->At(1));
+  const Instance& expected = Instance::CheckedHandle(arguments->NativeArgAt(0));
+  const Instance& actual = Instance::CheckedHandle(arguments->NativeArgAt(1));
   if (!expected.Equals(actual)) {
     OS::Print("expected: '%s' actual: '%s'\n",
         expected.ToCString(), actual.ToCString());
     FATAL("Unhandled_equals fails.\n");
   }
 }
 
 
 void FUNCTION_NAME(Unhandled_invoke)(Dart_NativeArguments args) {
   // Invoke the specified entry point.
@@ skipping 92 matching lines @@
       "  UnhandledExceptions.equals(3, Second.method3(1));\n"
       "}";
   Dart_Handle lib = TestCase::LoadTestScript(
       kScriptChars,
       reinterpret_cast<Dart_NativeEntryResolver>(native_lookup));
   EXPECT_VALID(Dart_Invoke(lib, NewString("testMain"), 0, NULL));
 }
 #endif  // defined(TARGET_ARCH_IA32) || defined(TARGET_ARCH_X64).
 
 }  // namespace dart