Move SetObjectPrototype to JSObject

src/objects.cc

Index: src/objects.cc
diff --git a/src/objects.cc b/src/objects.cc
index 6f38bdc5872084c4bdeb673b954804fdbf2893ab..120d8edfe8704cc1143887a2283ac86427663f4f 100644
--- a/src/objects.cc
+++ b/src/objects.cc
@@ -3326,6 +3326,15 @@ void JSObject::MigrateToMap(Handle<JSObject> object, Handle<Map> new_map,
   // When adding code here, add a DisallowHeapAllocation too.
 }
 
+void JSObject::ForceSetPrototype(Handle<JSObject> object,
+                                 Handle<Object> proto) {
+  // object.__proto__ = proto;
+  Handle<Map> old_map = Handle<Map>(object->map());
+  Handle<Map> new_map = Map::Copy(old_map, "ForceSetPrototype");
+  Map::SetPrototype(new_map, proto, FAST_PROTOTYPE);
+  JSObject::MigrateToMap(object, new_map);
+}
+
 int Map::NumberOfFields() {
   DescriptorArray* descriptors = instance_descriptors();
   int result = 0;