Add "own" symbols support.

src/factory.cc

 // Copyright 2014 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/factory.h"
 
 #include "src/allocation-site-scopes.h"
 #include "src/conversions.h"
 #include "src/isolate-inl.h"
 #include "src/macro-assembler.h"
@@ skipping 645 matching lines @@
 }
 
 
 Handle<Symbol> Factory::NewPrivateSymbol() {
   Handle<Symbol> symbol = NewSymbol();
   symbol->set_is_private(true);
   return symbol;
 }
 
 
+Handle<Symbol> Factory::NewPrivateOwnSymbol() {
+  Handle<Symbol> symbol = NewSymbol();
+  symbol->set_is_private(true);
+  symbol->set_is_own(true);
+  return symbol;
+}
+
+
 Handle<Context> Factory::NewNativeContext() {
   Handle<FixedArray> array = NewFixedArray(Context::NATIVE_CONTEXT_SLOTS);
   array->set_map_no_write_barrier(*native_context_map());
   Handle<Context> context = Handle<Context>::cast(array);
   context->set_js_array_maps(*undefined_value());
   DCHECK(context->IsNativeContext());
   return context;
 }
 
 
@@ skipping 1689 matching lines @@
   return Handle<Object>::null();
 }
 
 
 Handle<Object> Factory::ToBoolean(bool value) {
   return value ? true_value() : false_value();
 }
 
 
 } }  // namespace v8::internal