MuteSource Audio During Full Screen Cast

media/audio/win/audio_low_latency_input_win.h

Index: media/audio/win/audio_low_latency_input_win.h
diff --git a/media/audio/win/audio_low_latency_input_win.h b/media/audio/win/audio_low_latency_input_win.h
index 2f718f91523b09cbbfe1ed58c7440825e16606e9..eff9d9421f8bc041c2f5422dcedebf76cc20e79d 100644
--- a/media/audio/win/audio_low_latency_input_win.h
+++ b/media/audio/win/audio_low_latency_input_win.h
@@ -57,6 +57,7 @@
 #define MEDIA_AUDIO_WIN_AUDIO_LOW_LATENCY_INPUT_WIN_H_
 
 #include <Audioclient.h>
+#include <endpointvolume.h>
 #include <MMDeviceAPI.h>
 #include <stddef.h>
 #include <stdint.h>
@@ -196,6 +197,10 @@ class MEDIA_EXPORT WASAPIAudioInputStream
   // This interface does only work with shared-mode streams.
   base::win::ScopedComPtr<ISimpleAudioVolume> simple_audio_volume_;
 
+  // The IAudioEndpointVolume allows a client to control the volume level of
+  // the whole system.
+  base::win::ScopedComPtr<IAudioEndpointVolume> system_audio_volume_;
+
   // The audio engine will signal this event each time a buffer has been
   // recorded.
   base::win::ScopedHandle audio_samples_ready_event_;
@@ -207,6 +212,12 @@ class MEDIA_EXPORT WASAPIAudioInputStream
   // callback.
   std::unique_ptr<media::AudioBus> audio_bus_;
 
+  // Never set it through external API. Only used when |device_id_| ==
+  // kLoopbackWithMuteDeviceId.
+  // True, if we have muted the system audio for the stream capturing, and
+  // indicates that we need to unmute the system audio when stopping capturing.
+  bool mute_done_;
+
   DISALLOW_COPY_AND_ASSIGN(WASAPIAudioInputStream);
 };