Reland "[strong] Object literals create strong objects"

src/factory.cc

Index: src/factory.cc
diff --git a/src/factory.cc b/src/factory.cc
index e966e5ca949324294a70e7b4f3acc568790e0754..06373d2d8a39f62c0f98db6fd4978270f486f350 100644
--- a/src/factory.cc
+++ b/src/factory.cc
@@ -2339,14 +2339,18 @@ Handle<JSWeakMap> Factory::NewJSWeakMap() {
 
 Handle<Map> Factory::ObjectLiteralMapFromCache(Handle<Context> context,
                                                int number_of_properties,
+                                               bool is_strong,
                                                bool* is_result_from_cache) {
   const int kMapCacheSize = 128;
 
   // We do not cache maps for too many properties or when running builtin code.
-  if (number_of_properties > kMapCacheSize ||
+  // TODO(rossberg): cache strong maps properly
+  if (number_of_properties > kMapCacheSize || is_strong ||
       isolate()->bootstrapper()->IsActive()) {
     *is_result_from_cache = false;
-    return Map::Create(isolate(), number_of_properties);
+    Handle<Map> map = Map::Create(isolate(), number_of_properties);
+    if (is_strong) map->set_is_strong(true);
+    return map;
   }
   *is_result_from_cache = true;
   if (number_of_properties == 0) {