Use weak cells in dependent code.

src/objects-debug.cc

Index: src/objects-debug.cc
diff --git a/src/objects-debug.cc b/src/objects-debug.cc
index e6c231ecc64094ebed85666b5a301fa75f6d4573..a532d5f9336dcd6efef696f796f313d3c1504f42 100644
--- a/src/objects-debug.cc
+++ b/src/objects-debug.cc
@@ -673,6 +673,7 @@ void Code::CodeVerify() {
 
 void Code::VerifyEmbeddedObjectsDependency() {
   if (!CanContainWeakObjects()) return;
+  WeakCell* cell = CachedWeakCell();
   DisallowHeapAllocation no_gc;
   Isolate* isolate = GetIsolate();
   HandleScope scope(isolate);
@@ -683,13 +684,13 @@ void Code::VerifyEmbeddedObjectsDependency() {
       if (obj->IsMap()) {
         Map* map = Map::cast(obj);
         CHECK(map->dependent_code()->Contains(DependentCode::kWeakCodeGroup,
-                                              this));
+                                              cell));
       } else if (obj->IsJSObject()) {
         Object* raw_table = GetIsolate()->heap()->weak_object_to_code_table();
         WeakHashTable* table = WeakHashTable::cast(raw_table);
         Handle<Object> key_obj(obj, isolate);
-        CHECK(DependentCode::cast(table->Lookup(key_obj))->Contains(
-            DependentCode::kWeakCodeGroup, this));
+        CHECK(DependentCode::cast(table->Lookup(key_obj))
+                  ->Contains(DependentCode::kWeakCodeGroup, cell));
       }
     }
   }