Allow the AudioLowLatencyInputOutput tests to run on bots where audio hardware is available.

media/audio/win/audio_low_latency_output_win_unittest.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <windows.h>
 #include <mmsystem.h>
 
 #include "base/basictypes.h"
 #include "base/environment.h"
 #include "base/file_util.h"
@@ skipping 125 matching lines @@
   int file_size_;
   int pos_;
   base::Time previous_call_time_;
   FILE* text_file_;
   size_t elements_to_write_;
 };
 
 // Convenience method which ensures that we are not running on the build
 // bots and that at least one valid output device can be found.
 static bool CanRunAudioTests(AudioManager* audio_man) {
-  if (NULL == audio_man)
-    return false;
-
-  scoped_ptr<base::Environment> env(base::Environment::Create());
-  if (env->HasVar("CHROME_HEADLESS"))
-    return false;
   // TODO(henrika): note that we use Wave today to query the number of
   // existing output devices.
-  return audio_man->HasAudioOutputDevices();
+  bool output = audio_man->HasAudioOutputDevices();
+  LOG_IF(WARNING, !output) << "No output devices detected.";
+  return output;
 }
 
 // Convenience method which creates a default AudioOutputStream object but
 // also allows the user to modify the default settings.
 class AudioOutputStreamWrapper {
  public:
   explicit AudioOutputStreamWrapper(AudioManager* audio_manager)
       : com_init_(ScopedCOMInitializer::kMTA),
         audio_man_(audio_manager),
         format_(AudioParameters::AUDIO_PCM_LOW_LATENCY),
@@ skipping 371 matching lines @@
 
   aos->Start(&file_source);
   base::PlatformThread::Sleep(file_duration_ms);
   aos->Stop();
 
   LOG(INFO) << ">> File playout has stopped.";
   aos->Close();
 }
 
 }  // namespace media