[runtime] Remove useless IN builtin.

src/runtime/runtime-object.cc

Index: src/runtime/runtime-object.cc
diff --git a/src/runtime/runtime-object.cc b/src/runtime/runtime-object.cc
index 5945488831e9a705881845f988db47d91e5f9753..6287c98f3eb00e43a783a9df1edfe6d59301c246 100644
--- a/src/runtime/runtime-object.cc
+++ b/src/runtime/runtime-object.cc
@@ -753,28 +753,28 @@ RUNTIME_FUNCTION(Runtime_HasOwnProperty) {
 }
 
 
+// ES6 section 12.9.3, operator in.
 RUNTIME_FUNCTION(Runtime_HasProperty) {
   HandleScope scope(isolate);
-  DCHECK(args.length() == 2);
-  CONVERT_ARG_HANDLE_CHECKED(JSReceiver, receiver, 0);
-  CONVERT_ARG_HANDLE_CHECKED(Object, key, 1);
+  DCHECK_EQ(2, args.length());
+  CONVERT_ARG_HANDLE_CHECKED(Object, key, 0);
+  CONVERT_ARG_HANDLE_CHECKED(Object, object, 1);
+
+  // Check that {object} is actually a receiver.
+  if (!object->IsJSReceiver()) {
+    THROW_NEW_ERROR_RETURN_FAILURE(
+        isolate,
+        NewTypeError(MessageTemplate::kInvalidInOperatorUse, key, object));
+  }
+  Handle<JSReceiver> receiver = Handle<JSReceiver>::cast(object);
 
+  // Convert the {key} to a name.
   Handle<Name> name;
   ASSIGN_RETURN_FAILURE_ON_EXCEPTION(isolate, name,
                                      Object::ToName(isolate, key));
-  Maybe<bool> maybe = JSReceiver::HasProperty(receiver, name);
-  if (!maybe.IsJust()) return isolate->heap()->exception();
-  return isolate->heap()->ToBoolean(maybe.FromJust());
-}
 
-
-RUNTIME_FUNCTION(Runtime_HasElement) {
-  HandleScope scope(isolate);
-  DCHECK(args.length() == 2);
-  CONVERT_ARG_HANDLE_CHECKED(JSReceiver, receiver, 0);
-  CONVERT_SMI_ARG_CHECKED(index, 1);
-
-  Maybe<bool> maybe = JSReceiver::HasElement(receiver, index);
+  // Lookup the {name} on {receiver}.
+  Maybe<bool> maybe = JSReceiver::HasProperty(receiver, name);
   if (!maybe.IsJust()) return isolate->heap()->exception();
   return isolate->heap()->ToBoolean(maybe.FromJust());
 }