Use AudioManager::CreateForTesting for unittests.

media/audio/audio_manager_unittest.cc

Index: media/audio/audio_manager_unittest.cc
diff --git a/media/audio/audio_manager_unittest.cc b/media/audio/audio_manager_unittest.cc
index db0196a5d80941e61b1c2dfd70fae9c998d31c9d..9c50d62c311c319ec4ed75116a277a7b5fdf9e81 100644
--- a/media/audio/audio_manager_unittest.cc
+++ b/media/audio/audio_manager_unittest.cc
@@ -63,9 +63,7 @@ struct TestAudioManagerFactory<AudioManagerPulse> {
 template <>
 struct TestAudioManagerFactory<std::nullptr_t> {
   static ScopedAudioManagerPtr Create(AudioLogFactory* audio_log_factory) {
-    return AudioManager::Create(base::ThreadTaskRunnerHandle::Get(),
-                                base::ThreadTaskRunnerHandle::Get(), nullptr,
-                                audio_log_factory);
+    return AudioManager::CreateForTesting(base::ThreadTaskRunnerHandle::Get());
   }
 };
 }  // namespace