Added a Isolate* parameter to Serializer::enabled().

src/serialize.cc

Index: src/serialize.cc
diff --git a/src/serialize.cc b/src/serialize.cc
index e5694ca9004a59b8bff0d41239b4a8cbebb80ff9..16eb6f2cb546aff226d5351dc21852db9694240e 100644
--- a/src/serialize.cc
+++ b/src/serialize.cc
@@ -1377,7 +1377,7 @@ void Serializer::VisitPointers(Object** start, Object** end) {
 // deserialized objects.
 void SerializerDeserializer::Iterate(Isolate* isolate,
                                      ObjectVisitor* visitor) {
-  if (Serializer::enabled()) return;
+  if (Serializer::enabled(isolate)) return;
   for (int i = 0; ; i++) {
     if (isolate->serialize_partial_snapshot_cache_length() <= i) {
       // Extend the array ready to get a value from the visitor when