Temporarily CHECK use after free in Value

mojo/common/values_struct_traits.h

Index: mojo/common/values_struct_traits.h
diff --git a/mojo/common/values_struct_traits.h b/mojo/common/values_struct_traits.h
index befcf3a6ea2816dd56e56f0a50933d9cec3548e0..766b90b49ec7194ac816d7a81041d40c632b2770 100644
--- a/mojo/common/values_struct_traits.h
+++ b/mojo/common/values_struct_traits.h
@@ -135,6 +135,10 @@ struct UnionTraits<common::mojom::ValueDataView, base::Value> {
         return common::mojom::ValueDataView::Tag::DICTIONARY_VALUE;
       case base::Value::Type::LIST:
         return common::mojom::ValueDataView::Tag::LIST_VALUE;
+      case base::Value::Type::DELETED:
+        // TODO(crbug.com/697817): This means a use-after-free.
+        CHECK(false);
+        return common::mojom::ValueDataView::Tag::NULL_VALUE;
     }
     NOTREACHED();
     return common::mojom::ValueDataView::Tag::NULL_VALUE;