ES6: Add support for Map.prototype.forEach and Set.prototype.forEach

src/factory.h

Index: src/factory.h
diff --git a/src/factory.h b/src/factory.h
index ae861baa78de18037d41a0ac6fdc40df9ddef6ba..46bd56762b2c6269e41f1ad82bf40d66d663e728 100644
--- a/src/factory.h
+++ b/src/factory.h
@@ -593,6 +593,8 @@ class Factory V8_FINAL {
   // Converts the given boolean condition to JavaScript boolean value.
   Handle<Object> ToBoolean(bool value);
 
+  Handle<JSObject> CreateIteratorResultObject(Handle<Object> value, bool done);
+
  private:
   Isolate* isolate() { return reinterpret_cast<Isolate*>(this); }