[runtime] Migrate several Date builtins to C++.

src/runtime/runtime-object.cc

Index: src/runtime/runtime-object.cc
diff --git a/src/runtime/runtime-object.cc b/src/runtime/runtime-object.cc
index aa077c57464d046e7b5f98bb7dad4d3ab3bb01c2..75ddb7bc22b66e7d2efc11ded838b6e9e81d1ac2 100644
--- a/src/runtime/runtime-object.cc
+++ b/src/runtime/runtime-object.cc
@@ -795,46 +795,15 @@ RUNTIME_FUNCTION(Runtime_AllocateHeapNumber) {
 }
 
 
-static Object* Runtime_NewObjectHelper(Isolate* isolate,
-                                       Handle<JSFunction> constructor,
-                                       Handle<JSReceiver> new_target,
-                                       Handle<AllocationSite> site) {
-  DCHECK(constructor->IsConstructor());
-
-  // If called through new, new.target can be:
-  // - a subclass of constructor,
-  // - a proxy wrapper around constructor, or
-  // - the constructor itself.
-  // If called through Reflect.construct, it's guaranteed to be a constructor by
-  // REFLECT_CONSTRUCT_PREPARE.
-  DCHECK(new_target->IsConstructor());
-
-  DCHECK(!constructor->has_initial_map() ||
-         constructor->initial_map()->instance_type() != JS_FUNCTION_TYPE);
-
-  Handle<Map> initial_map;
-  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
-      isolate, initial_map,
-      JSFunction::GetDerivedMap(isolate, constructor, new_target));
-
-  Handle<JSObject> result =
-      isolate->factory()->NewJSObjectFromMap(initial_map, NOT_TENURED, site);
-
-  isolate->counters()->constructed_objects()->Increment();
-  isolate->counters()->constructed_objects_runtime()->Increment();
-
-  return *result;
-}
-
-
 RUNTIME_FUNCTION(Runtime_NewObject) {
   HandleScope scope(isolate);
-  DCHECK(args.length() == 2);
-  CONVERT_ARG_HANDLE_CHECKED(JSFunction, constructor, 0);
+  DCHECK_EQ(2, args.length());
+  CONVERT_ARG_HANDLE_CHECKED(JSFunction, target, 0);
   CONVERT_ARG_HANDLE_CHECKED(JSReceiver, new_target, 1);
-
-  return Runtime_NewObjectHelper(isolate, constructor, new_target,
-                                 Handle<AllocationSite>::null());
+  Handle<JSObject> result;
+  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(isolate, result,
+                                     JSObject::New(target, new_target));
+  return *result;
 }