Switching WebRTC browser test from AudioManager::HasAudioOutputDevices() to AudioSystem interface.

media/audio/audio_system_impl.h

 // Copyright 2017 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.
 
 #ifndef MEDIA_AUDIO_AUDIO_SYSTEM_IMPL_H_
 #define MEDIA_AUDIO_AUDIO_SYSTEM_IMPL_H_
 
 #include "media/audio/audio_system.h"
 
 namespace base {
@@ skipping 13 matching lines @@
   void GetInputStreamParameters(
       const std::string& device_id,
       OnAudioParamsCallback on_params_cb) const override;
 
   void GetOutputStreamParameters(
       const std::string& device_id,
       OnAudioParamsCallback on_params_cb) const override;
 
   void HasInputDevices(OnBoolCallback on_has_devices_cb) const override;
 
+  void HasOutputDevices(OnBoolCallback on_has_devices_cb) const override;
+
   void GetDeviceDescriptions(OnDeviceDescriptionsCallback on_descriptions_cp,
                              bool for_input) override;
 
   base::SingleThreadTaskRunner* GetTaskRunner() const override;
 
   AudioManager* GetAudioManager() const override;
 
  protected:
   AudioSystemImpl(AudioManager* audio_manager);
 
  private:
   AudioManager* const audio_manager_;
 
   DISALLOW_COPY_AND_ASSIGN(AudioSystemImpl);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_AUDIO_AUDIO_SYSTEM_IMPL_H_