Detect AudioInputStream muting and propagate to MediaStreamAudioSource.

media/audio/audio_input_controller.h

Index: media/audio/audio_input_controller.h
diff --git a/media/audio/audio_input_controller.h b/media/audio/audio_input_controller.h
index ff0022dbee32629e567ac114d657a84d00728bb3..39dbb47fc4363059877d03abe7ddc1e8b1b10169 100644
--- a/media/audio/audio_input_controller.h
+++ b/media/audio/audio_input_controller.h
@@ -14,6 +14,7 @@
 #include "base/files/file.h"
 #include "base/memory/weak_ptr.h"
 #include "base/single_thread_task_runner.h"
+#include "base/timer/timer.h"
 #include "media/audio/audio_debug_file_writer.h"
 #include "media/audio/audio_io.h"
 #include "media/audio/audio_manager_base.h"
@@ -107,6 +108,7 @@ class MEDIA_EXPORT AudioInputController
                          ErrorCode error_code) = 0;
     virtual void OnLog(AudioInputController* controller,
                        const std::string& message) = 0;
+    virtual void OnMuted(AudioInputController* controller, bool is_muted) = 0;
 
    protected:
     virtual ~EventHandler() {}
@@ -323,6 +325,8 @@ class MEDIA_EXPORT AudioInputController
                        float* average_power_dbfs,
                        int* mic_volume_percent);
 
+  void CheckMutedState();
+
   static StreamType ParamsToStreamType(const AudioParameters& params);
 
   // Gives access to the task runner of the creating thread.
@@ -367,6 +371,9 @@ class MEDIA_EXPORT AudioInputController
   // Time when the stream started recording.
   base::TimeTicks stream_create_time_;
 
+  bool is_muted_ = false;
+  std::unique_ptr<base::RepeatingTimer> check_muted_state_timer_;

[Max Morin, 2017/06/02 09:56:05]

Does this need to be allocated separately? Otherwise, consider using
base::Optional to save an allocation and improve memory locality.

[ossu-chromium, 2017/06/02 10:48:00]

I'll try to get it as a regular object instead, see if that works.

[Guido Urdaneta, 2017/06/02 13:33:45]

Using a regular object should suffice. From the documentation of timer.h:

// Sample RepeatingTimer usage:
//
//   class MyClass {
//    public:
//     void StartDoingStuff() {
//       timer_.Start(FROM_HERE, TimeDelta::FromSeconds(1),
//                    this, &MyClass::DoStuff);
//     }
//     void StopDoingStuff() {
//       timer_.Stop();
//     }
//    private:
//     void DoStuff() {
//       // This method is called every second to do stuff.
//       ...
//     }
//     base::RepeatingTimer timer_;
//   };

A code search shows both kinds of usage.

+
 #if BUILDFLAG(ENABLE_WEBRTC)
   // Used for audio debug recordings. Accessed on audio thread.
   AudioDebugRecordingHelper debug_recording_helper_;