[runtime] We don't need an actual instance type for JSIteratorResult.

src/factory.h

 // Copyright 2014 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.
 
 #ifndef V8_FACTORY_H_
 #define V8_FACTORY_H_
 
 #include "src/isolate.h"
 #include "src/messages.h"
 #include "src/type-feedback-vector.h"
@@ skipping 451 matching lines @@
   Handle<JSDataView> NewJSDataView(Handle<JSArrayBuffer> buffer,
                                    size_t byte_offset, size_t byte_length);
 
   Handle<JSMap> NewJSMap();
   Handle<JSSet> NewJSSet();
 
   // TODO(aandrey): Maybe these should take table, index and kind arguments.
   Handle<JSMapIterator> NewJSMapIterator();
   Handle<JSSetIterator> NewJSSetIterator();
 
-  // Creates a new JSIteratorResult object with the arguments {value} and
-  // {done}.  Implemented according to ES6 section 7.4.7 CreateIterResultObject.
-  Handle<JSIteratorResult> NewJSIteratorResult(Handle<Object> value,
-                                               Handle<Object> done);
-
   // Allocates a bound function.
   MaybeHandle<JSBoundFunction> NewJSBoundFunction(
       Handle<JSReceiver> target_function, Handle<Object> bound_this,
       Vector<Handle<Object>> bound_args);
 
   // Allocates a Harmony proxy.
   Handle<JSProxy> NewJSProxy(Handle<JSReceiver> target,
                              Handle<JSReceiver> handler);
 
   // Reinitialize an JSGlobalProxy based on a constructor.  The object
@@ skipping 216 matching lines @@
   // Create a JSArray with no elements and no length.
   Handle<JSArray> NewJSArray(ElementsKind elements_kind,
                              Strength strength = Strength::WEAK,
                              PretenureFlag pretenure = NOT_TENURED);
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_FACTORY_H_