Revert preallocating of descriptors since right now getters and setters cause copying of descriptor…

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.h"
 #include "src/lookup.h"
 #include "src/messages.h"
@@ skipping 133 matching lines @@
   // Disable access checks while instantiating the object.
   AccessCheckDisableScope access_check_scope(isolate, obj);
 
   int i = 0;
   for (int c = 0; c < data->number_of_properties(); c++) {
     auto name = handle(Name::cast(properties.get(i++)), isolate);
     PropertyDetails details(Smi::cast(properties.get(i++)));
     PropertyAttributes attributes = details.attributes();
     PropertyKind kind = details.kind();
 
-    if (obj->map()->owns_descriptors() &&
-        obj->map()->instance_descriptors()->length() != 0 &&
-        obj->map()->instance_descriptors()->NumberOfSlackDescriptors() == 0 &&
-        TransitionArray::SearchTransition(obj->map(), kind, *name,
-                                          attributes) == NULL) {
-      Map::EnsureDescriptorSlack(handle(obj->map()),
-                                 data->number_of_properties() - c);
-    }
-
     if (kind == kData) {
       auto prop_data = handle(properties.get(i++), isolate);
 
       RETURN_ON_EXCEPTION(isolate, DefineDataProperty(isolate, obj, name,
                                                       prop_data, attributes),
                           JSObject);
     } else {
       auto getter = handle(properties.get(i++), isolate);
       auto setter = handle(properties.get(i++), isolate);
       RETURN_ON_EXCEPTION(isolate,
@@ skipping 397 matching lines @@
     Handle<AccessorInfo> accessor(AccessorInfo::cast(array->get(i)));
     JSObject::SetAccessor(result, accessor).Assert();
   }
 
   DCHECK(result->shared()->IsApiFunction());
   return result;
 }
 
 }  // namespace internal
 }  // namespace v8