Enable map transitions for accessor properties.

src/objects.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 4438 matching lines @@
 
 
 MaybeObject* JSObject::DefinePropertyAccessor(String* name,
                                               Object* getter,
                                               Object* setter,
                                               PropertyAttributes attributes) {
   // We could assert that the property is configurable here, but we would need
   // to do a lookup, which seems to be a bit of overkill.
   Heap* heap = GetHeap();
   bool only_attribute_changes = getter->IsNull() && setter->IsNull();
-  if (FLAG_fast_accessor_properties &&
-      HasFastProperties() && !only_attribute_changes) {
+  if (HasFastProperties() && !only_attribute_changes) {
     MaybeObject* getterOk = heap->undefined_value();
     if (!getter->IsNull()) {
       getterOk = DefineFastAccessor(name, ACCESSOR_GETTER, getter, attributes);
       if (getterOk->IsFailure()) return getterOk;
     }
 
     MaybeObject* setterOk = heap->undefined_value();
     if (getterOk != heap->null_value() && !setter->IsNull()) {
       setterOk = DefineFastAccessor(name, ACCESSOR_SETTER, setter, attributes);
       if (setterOk->IsFailure()) return setterOk;
@@ skipping 8725 matching lines @@
   set_year(Smi::FromInt(year), SKIP_WRITE_BARRIER);
   set_month(Smi::FromInt(month), SKIP_WRITE_BARRIER);
   set_day(Smi::FromInt(day), SKIP_WRITE_BARRIER);
   set_weekday(Smi::FromInt(weekday), SKIP_WRITE_BARRIER);
   set_hour(Smi::FromInt(hour), SKIP_WRITE_BARRIER);
   set_min(Smi::FromInt(min), SKIP_WRITE_BARRIER);
   set_sec(Smi::FromInt(sec), SKIP_WRITE_BARRIER);
 }
 
 } }  // namespace v8::internal