Make value of initialized_objects_ a pointer.

PiperOrigin-RevId: 458418975
diff --git a/lifetime_analysis/object_repository.h b/lifetime_analysis/object_repository.h
index 80a18a1..aea6b59 100644
--- a/lifetime_analysis/object_repository.h
+++ b/lifetime_analysis/object_repository.h
@@ -232,7 +232,7 @@
   // An object in this map may occur in other places too: `object_repository_`
   // if it is an lvalue, or `return_object_`. Or it may be a temporary in which
   // case it is only found in this map.
-  llvm::DenseMap<const clang::Expr*, Object> initialized_objects_;
+  llvm::DenseMap<const clang::Expr*, const Object*> initialized_objects_;
 
   std::optional<const Object*> this_object_;
   const Object* return_object_;