Add browser test for getusermedia and unavailable audio device.

media/audio/audio_manager.cc

Index: media/audio/audio_manager.cc
diff --git a/media/audio/audio_manager.cc b/media/audio/audio_manager.cc
index 097e4c9abc55df685efae712a682ddeb6558c0d4..30430bf58fad74f6e48e5dce5a7c851183777868 100644
--- a/media/audio/audio_manager.cc
+++ b/media/audio/audio_manager.cc
@@ -303,6 +303,10 @@ ScopedAudioManagerPtr CreateAudioManager(
     scoped_refptr<base::SingleThreadTaskRunner> worker_task_runner,
     AudioLogFactory* audio_log_factory);
 
+void AudioManager::SetMaxStreamCountForTesting(int max_input, int max_output) {
+  NOTREACHED();
+}
+
 AudioManager::AudioManager(
     scoped_refptr<base::SingleThreadTaskRunner> task_runner,
     scoped_refptr<base::SingleThreadTaskRunner> worker_task_runner)