[field type tracking] Fix handling of cleared WeakCells

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index b35d9ba9f7acabbb2ea559812f535433c85fb60c..4f57eade4d53ac1d24cfb962c520b6d6cfc5b179 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -5471,9 +5471,8 @@ class Map: public HeapObject {
   // TODO(ishell): moveit!
   static Handle<Map> GeneralizeAllFieldRepresentations(Handle<Map> map);
   MUST_USE_RESULT static Handle<HeapType> GeneralizeFieldType(
-      Handle<HeapType> type1,
-      Handle<HeapType> type2,
-      Isolate* isolate);
+      Representation rep1, Handle<HeapType> type1, Representation rep2,
+      Handle<HeapType> type2, Isolate* isolate);
   static void GeneralizeFieldType(Handle<Map> map, int modify_index,
                                   Representation new_representation,
                                   Handle<HeapType> new_field_type);