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..a56f4db368ff3b5e3c3869679cf4e0e813085c3a 100644
--- a/media/audio/audio_input_controller.h
+++ b/media/audio/audio_input_controller.h
@@ -13,7 +13,9 @@
 
 #include "base/files/file.h"
 #include "base/memory/weak_ptr.h"
+#include "base/optional.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 +109,11 @@ class MEDIA_EXPORT AudioInputController
                          ErrorCode error_code) = 0;
     virtual void OnLog(AudioInputController* controller,
                        const std::string& message) = 0;
+    // Initially, an AudioInputController is considered not muted. If the
+    // underlying stream is actually muted, an OnMuted callback will follow
+    // shortly after OnCreated. It is also called whenever the muted state of
+    // the underlying stream changes.
+    virtual void OnMuted(AudioInputController* controller, bool is_muted) = 0;
 
    protected:
     virtual ~EventHandler() {}
@@ -323,6 +330,8 @@ 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 +376,12 @@ class MEDIA_EXPORT AudioInputController
   // Time when the stream started recording.
   base::TimeTicks stream_create_time_;
 
+  bool is_muted_ = false;
+
+  // The timer needs to be destroyed on the correct thread, so we can't leave
+  // that to our destructor.
+  base::Optional<base::RepeatingTimer> check_muted_state_timer_;

[DaleCurtis, 2017/06/15 18:44:00]

Drop Optional in favor of just IsRunning().

[ossu-chromium, 2017/06/20 12:25:15]

I was quite sure I was unable to get the timer to work properly as a regular
member: I was hitting a thread check in the destructor. I've not been able to
replicate it now, though, so I'll put up a version which avoids the Optional,
see if one of the bots find anything.

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