ExtendStorageStub added, it is aimed for extending objects backing store when it runs out of space.

src/objects.cc

 // Copyright 2013 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/v8.h"
 
 #include "src/accessors.h"
 #include "src/allocation-site-scopes.h"
 #include "src/api.h"
 #include "src/arguments.h"
@@ skipping 1944 matching lines @@
         Handle<Object> value = isolate->factory()->NewHeapNumber(0, MUTABLE);
         FieldIndex index =
             FieldIndex::ForDescriptor(*new_map, new_map->LastAdded());
         object->FastPropertyAtPut(index, *value);
       }
       object->synchronized_set_map(*new_map);
       return;
     }
 
     DCHECK(number_of_fields == old_number_of_fields + 1);
-    // This migration is a transition from a map that has run out out property
+    // This migration is a transition from a map that has run out of property
     // space. Therefore it could be done by extending the backing store.
     Handle<FixedArray> old_storage = handle(object->properties(), isolate);
     Handle<FixedArray> new_storage =
         FixedArray::CopySize(old_storage, external);
 
     // Properly initialize newly added property.
     Handle<Object> value;
     if (details.representation().IsDouble()) {
       value = isolate->factory()->NewHeapNumber(0, MUTABLE);
     } else {
@@ skipping 1759 matching lines @@
     return false;
   }
   JSObject::MigrateToMap(object, new_map);
   if (FLAG_trace_migration) {
     object->PrintInstanceMigration(stdout, *original_map, object->map());
   }
   return true;
 }
 
 
-void JSObject::MigrateToNewProperty(Handle<JSObject> object,
-                                    Handle<Map> map,
-                                    Handle<Object> value) {
-  JSObject::MigrateToMap(object, map);
-  if (map->GetLastDescriptorDetails().type() != FIELD) return;
-  object->WriteToField(map->LastAdded(), *value);
-}
-
-
 void JSObject::WriteToField(int descriptor, Object* value) {
   DisallowHeapAllocation no_gc;
 
   DescriptorArray* desc = map()->instance_descriptors();
   PropertyDetails details = desc->GetDetails(descriptor);
 
   DCHECK(details.type() == FIELD);
 
   FieldIndex index = FieldIndex::ForDescriptor(map(), descriptor);
   if (details.representation().IsDouble()) {
@@ skipping 12602 matching lines @@
 #define ERROR_MESSAGES_TEXTS(C, T) T,
   static const char* error_messages_[] = {
       ERROR_MESSAGES_LIST(ERROR_MESSAGES_TEXTS)
   };
 #undef ERROR_MESSAGES_TEXTS
   return error_messages_[reason];
 }
 
 
 } }  // namespace v8::internal