Detect AudioInputStream muting and propagate to MediaStreamAudioSource.

content/renderer/media/audio_input_message_filter.cc

Index: content/renderer/media/audio_input_message_filter.cc
diff --git a/content/renderer/media/audio_input_message_filter.cc b/content/renderer/media/audio_input_message_filter.cc
index 46b4e4c44194b1c5b6dbac06c9e7134466640968..145215b5871edee38800a8b5235d43137e99c50b 100644
--- a/content/renderer/media/audio_input_message_filter.cc
+++ b/content/renderer/media/audio_input_message_filter.cc
@@ -87,6 +87,7 @@ bool AudioInputMessageFilter::OnMessageReceived(const IPC::Message& message) {
     IPC_MESSAGE_HANDLER(AudioInputMsg_NotifyStreamCreated,
                         OnStreamCreated)
     IPC_MESSAGE_HANDLER(AudioInputMsg_NotifyStreamError, OnStreamError)
+    IPC_MESSAGE_HANDLER(AudioInputMsg_NotifyStreamMuted, OnStreamMuted)
     IPC_MESSAGE_UNHANDLED(handled = false)
   IPC_END_MESSAGE_MAP()
   return handled;
@@ -156,6 +157,17 @@ void AudioInputMessageFilter::OnStreamError(int stream_id) {
   delegate->OnError();
 }
 
+void AudioInputMessageFilter::OnStreamMuted(int stream_id, bool is_muted) {
+  DCHECK(io_task_runner_->BelongsToCurrentThread());
+  media::AudioInputIPCDelegate* delegate = delegates_.Lookup(stream_id);
+  if (!delegate) {
+    DLOG(WARNING) << "Got audio stream muted event for a non-existent or "
+                     "removed audio renderer.";
+    return;
+  }
+  delegate->OnMuted(is_muted);
+}
+
 AudioInputMessageFilter::AudioInputIPCImpl::AudioInputIPCImpl(
     const scoped_refptr<AudioInputMessageFilter>& filter,
     int render_frame_id)