[Chromoting] Audio playback won't work after switching default playback device

remoting/host/audio_capturer_win.h

Index: remoting/host/audio_capturer_win.h
diff --git a/remoting/host/audio_capturer_win.h b/remoting/host/audio_capturer_win.h
index d53920a43d9284f6b4ebd8f7d8f5f626b568a87e..db8c5d7da5e7a0cd14e372dab93444a573f0c83e 100644
--- a/remoting/host/audio_capturer_win.h
+++ b/remoting/host/audio_capturer_win.h
@@ -31,6 +31,16 @@ class AudioCapturerWin : public AudioCapturer {
   bool Start(const PacketCapturedCallback& callback) override;
 
  private:
+  // The implementation of IMMNotificationClient, to set
+  // default_audio_device_changed_ in OnDefaultDeviceChanged function.

[Sergey Ulanov, 2016/07/20 17:28:34]

nit:
s/default_audio_device_changed_/|default_audio_device_changed_|/
s/OnDefaultDeviceChanged function/OnDefaultDeviceChanged()/

[Hzj_jie, 2016/07/20 20:43:14]

Since default_audio_device_changed_ has been moved to MMNotificationClient, I
updated the comment.

+  class MMNotificationClient;
+  friend class MMNotificationClient;

[Sergey Ulanov, 2016/07/20 17:28:34]

if you move default_audio_device_changed_ to MMNotificationClient (with a
get-and-reset access method) then it won't need to be a friend.

[Hzj_jie, 2016/07/20 20:43:14]

Done.

+
+  // Resets and reinitializes default audio device related components. These
+  // components must be recreated once the default audio device changed. Returns
+  // false if initialization failed.
+  bool ResetAndInitialize();
+
   // Receives all packets from the audio capture endpoint buffer and pushes them
   // to the network.
   void DoCapture();
@@ -55,11 +65,17 @@ class AudioCapturerWin : public AudioCapturer {
   AudioSilenceDetector silence_detector_;
 
   base::win::ScopedCoMem<WAVEFORMATEX> wave_format_ex_;
+  base::win::ScopedComPtr<IMMDeviceEnumerator> mm_device_enumerator_;
   base::win::ScopedComPtr<IAudioCaptureClient> audio_capture_client_;
   base::win::ScopedComPtr<IAudioClient> audio_client_;
   base::win::ScopedComPtr<IMMDevice> mm_device_;
   base::win::ScopedComPtr<IAudioEndpointVolume> audio_volume_;
 
+  // Whether the default audio device has been changed recently. If this value
+  // is true, we need to recreate all audio components.
+  bool default_audio_device_changed_ = false;
+  const std::unique_ptr<MMNotificationClient> mm_notification_client_;
+
   HRESULT last_capture_error_;
 
   base::ThreadChecker thread_checker_;