Mojom frontend: Allow non-reference types in non-zero versions of a struct.

mojom/mojom_parser/parser/computed_data_test.go

Index: mojom/mojom_parser/parser/computed_data_test.go
diff --git a/mojom/mojom_parser/parser/computed_data_test.go b/mojom/mojom_parser/parser/computed_data_test.go
index 012e39aea4ac6fa2ea48c523116d68c1e44a80bd..2f4bb1ff8ce3521b880b0298c0a557679d4bf84a 100644
--- a/mojom/mojom_parser/parser/computed_data_test.go
+++ b/mojom/mojom_parser/parser/computed_data_test.go
@@ -156,7 +156,7 @@ func TestMinVersionErrors(t *testing.T) {
 	};`
 		test.addTestCase(contents, []string{
 			"Invalid type for field z: array<int32>.",
-			"Non-nullable fields are only allowed in version 0 of of a struct.",
+			"Non-nullable reference fields are only allowed in version 0 of of a struct.",
 			"This field's MinVersion is 1."})
 	}