Add NativeWeakMap to v8.h

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/base/bits.h"
 #include "src/conversions.h"
 #include "src/isolate-inl.h"
@@ skipping 2219 matching lines @@
   Handle<JSObject> result = NewJSObjectFromMap(map);
   Handle<Smi> value(Smi::FromInt(length), isolate());
   Object::SetProperty(result, length_string(), value, STRICT).Assert();
   if (!strict_mode_callee) {
     Object::SetProperty(result, callee_string(), callee, STRICT).Assert();
   }
   return result;
 }
 
 
+Handle<JSWeakMap> Factory::NewJSWeakMap() {
+  // TODO(adamk): Currently the map is only created three times per
+  // isolate. If it's created more often, the map should be moved into the
+  // strong root list.
+  Handle<Map> map = NewMap(JS_WEAK_MAP_TYPE, JSWeakMap::kSize);
+  return Handle<JSWeakMap>::cast(NewJSObjectFromMap(map));
+}
+
+
 Handle<Map> Factory::ObjectLiteralMapFromCache(Handle<Context> context,
                                                int number_of_properties,
                                                bool* is_result_from_cache) {
   const int kMapCacheSize = 128;
 
   if (number_of_properties > kMapCacheSize) {
     *is_result_from_cache = false;
     return Map::Create(isolate(), number_of_properties);
   }
   *is_result_from_cache = true;
@@ skipping 70 matching lines @@
   return Handle<Object>::null();
 }
 
 
 Handle<Object> Factory::ToBoolean(bool value) {
   return value ? true_value() : false_value();
 }
 
 
 } }  // namespace v8::internal