MuteSource Audio During Full Screen Cast

media/audio/cras/cras_input.h

Index: media/audio/cras/cras_input.h
diff --git a/media/audio/cras/cras_input.h b/media/audio/cras/cras_input.h
index e9f72ff5f36a94e503abf5f8fd6093d478b41827..420cd9b1a4e1a5b649c9617ae14d4e96a0fe11b0 100644
--- a/media/audio/cras/cras_input.h
+++ b/media/audio/cras/cras_input.h
@@ -114,6 +114,10 @@ class MEDIA_EXPORT CrasInputStream : public AgcAudioStream<AudioInputStream> {
   // True if the stream is a system-wide loopback stream.
   bool is_loopback_;
 
+  // True if we want to mute system audio during capturing.
+  bool mute_system_audio_;
+  bool mute_done_;
+
   std::unique_ptr<AudioBus> audio_bus_;
 
   DISALLOW_COPY_AND_ASSIGN(CrasInputStream);