[objective_c] Use user_defines to gate test utilities in build hook (Fixes #2999)

Author: Gurleen-kansray

pkgs/objective_c/CHANGELOG.md

@@ -7,6 +7,8 @@
   Objective-C.
 - Fix a [bug](https://github.com/dart-lang/native/issues/3290) where missing
   debug symbols caused app store valiadtion warnings.
+- Moved test utilities to use `user_defines` in the build hook instead of a
+  separate helper package (fixes [#2999](https://github.com/dart-lang/native/issues/2999)).
 
 ## 9.3.0
 - `autoReleasePool` now returns the value produced by its callback.

pkgs/objective_c/hook/build.dart

@@ -13,10 +13,6 @@ const objCFlags = ['-x', 'objective-c', '-fobjc-arc'];
 
 const assetName = 'objective_c.dylib';
 
-// TODO(https://github.com/dart-lang/native/issues/2272): Remove this from the
-// main build.
-const testFiles = ['test/util.c'];
-
 final logger = Logger('')
   ..level = Level.INFO
   ..onRecord.listen((record) {
@@ -59,13 +55,9 @@ void main(List<String> args) async {
       }
     }
 
-    // Only include the test utils on mac OS. They use memory functions that
-    // aren't supported on iOS, like mach_vm_region. We don't need them on iOS
-    // anyway since we only run memory tests on mac.
-    if (os == OS.macOS) {
-      cFiles.addAll(
-        testFiles.map((f) => input.packageRoot.resolve(f).toFilePath()),
-      );
+    final includeTestUtils = input.userDefines['include_test_utils'] == 'true';
+    if (includeTestUtils) {
+      cFiles.add(input.packageRoot.resolve('test/util.c').toFilePath());
     }
 
     final sysroot = sdkPath(codeConfig);

pkgs/objective_c/pubspec.yaml

@@ -1,7 +1,6 @@
 # Copyright (c) 2024, the Dart project authors.  Please see the AUTHORS file
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE file.
-
 name: objective_c
 description: 'A library to access Objective C from Flutter that acts as a support library for package:ffigen.'
 version: 9.4.0-wip
@@ -45,3 +44,7 @@ dependency_overrides:
     path: ../hooks
   native_toolchain_c:
     path: ../native_toolchain_c
+
+hook:
+  user_defines:
+    include_test_utils: "false"