[es6] Support optional "receiver" argument in Reflect.get.

src/objects-inl.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
 // Review notes:
 //
 // - The use of macros in these inline functions may seem superfluous
 // but it is absolutely needed to make sure gcc generates optimal
 // code. gcc is not happy when attempting to inline too deep.
 //
@@ skipping 7241 matching lines @@
 
 MaybeHandle<Object> Object::GetPropertyOrElement(Handle<Object> object,
                                                  Handle<Name> name,
                                                  LanguageMode language_mode) {
   LookupIterator it =
       LookupIterator::PropertyOrElement(name->GetIsolate(), object, name);
   return GetProperty(&it, language_mode);
 }
 
 
+MaybeHandle<Object> Object::GetPropertyOrElement(Handle<JSReceiver> holder,
+                                                 Handle<Name> name,
+                                                 Handle<Object> receiver,
+                                                 LanguageMode language_mode) {
+  LookupIterator it = LookupIterator::PropertyOrElement(
+      name->GetIsolate(), receiver, name, holder);
+  return GetProperty(&it, language_mode);
+}
+
+
 Maybe<bool> JSReceiver::HasProperty(Handle<JSReceiver> object,
                                     Handle<Name> name) {
   // Call the "has" trap on proxies.
   if (object->IsJSProxy()) {
     Handle<JSProxy> proxy = Handle<JSProxy>::cast(object);
     return JSProxy::HasPropertyWithHandler(proxy, name);
   }
 
   Maybe<PropertyAttributes> result = GetPropertyAttributes(object, name);
   return result.IsJust() ? Just(result.FromJust() != ABSENT) : Nothing<bool>();
@@ skipping 845 matching lines @@
 #undef WRITE_INT64_FIELD
 #undef READ_BYTE_FIELD
 #undef WRITE_BYTE_FIELD
 #undef NOBARRIER_READ_BYTE_FIELD
 #undef NOBARRIER_WRITE_BYTE_FIELD
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_OBJECTS_INL_H_