Speed up the LookupIterator

src/api-natives.cc

 // Copyright 2015 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.
 
 #include "src/api-natives.h"
 
 #include "src/api.h"
 #include "src/isolate-inl.h"
 #include "src/lookup.h"
 #include "src/messages.h"
@@ skipping 527 matching lines @@
       internal_field_count =
           Smi::cast(instance_template->internal_field_count())->value();
     }
 
     // TODO(svenpanne) Kill ApiInstanceType and refactor things by generalizing
     // JSObject::GetHeaderSize.
     int instance_size = kPointerSize * internal_field_count;
     InstanceType type;
     switch (instance_type) {
       case JavaScriptObjectType:
-        type = JS_OBJECT_TYPE;
+        if (!obj->needs_access_check() &&
+            obj->named_property_handler()->IsUndefined() &&
+            obj->indexed_property_handler()->IsUndefined()) {
+          type = JS_OBJECT_TYPE;
+        } else {
+          type = JS_SPECIAL_API_OBJECT_TYPE;
+        }
         instance_size += JSObject::kHeaderSize;
         break;
       case GlobalObjectType:
         type = JS_GLOBAL_OBJECT_TYPE;
         instance_size += JSGlobalObject::kSize;
         break;
       case GlobalProxyType:
         type = JS_GLOBAL_PROXY_TYPE;
         instance_size += JSGlobalProxy::kSize;
         break;
@@ skipping 62 matching lines @@
     map->set_is_callable();
     map->set_is_constructor(true);
   }
 
   DCHECK(result->shared()->IsApiFunction());
   return result;
 }
 
 }  // namespace internal
 }  // namespace v8