Detect AudioInputStream muting and propagate to MediaStreamAudioSource.

content/renderer/media/media_stream_source.cc

Index: content/renderer/media/media_stream_source.cc
diff --git a/content/renderer/media/media_stream_source.cc b/content/renderer/media/media_stream_source.cc
index 3334bfd57120d66fa4bbd13cac1a12a50d968479..97b34d8340b39df103fc558cfc74d61e3734890f 100644
--- a/content/renderer/media/media_stream_source.cc
+++ b/content/renderer/media/media_stream_source.cc
@@ -26,6 +26,14 @@ void MediaStreamSource::StopSource() {
   Owner().SetReadyState(blink::WebMediaStreamSource::kReadyStateEnded);
 }
 
+void MediaStreamSource::SetSourceMuted(bool is_muted) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  // TODO(ossu): Check that we only go between Muted and Live, not from Ended.

[ossu-chromium, 2017/06/01 15:56:59]

This looks like it's already be taken care of downstream, but maybe a sanity
check here would be useful?

[Max Morin, 2017/06/02 09:56:04]

Yes. Could you point out where this is taken care of?

[ossu-chromium, 2017/06/02 10:47:59]

MediaStreamTrack::SourceChangedState() checks if the current ReadyState is Ended
and just does nothing.
MediaStreamSource::SetReadyState also checks that the current ReadyState isn't
Ended before doing anything.
I could point to those in a comment. I'm wondering if a DCHECK here would be
good. We really shouldn't be sending mute/unmute notifications for a stream
that's ended, but maybe timing, threading and queuing sometimes would have that
happen? It would be sad if we crashed.

[Max Morin, 2017/06/05 07:01:38]

Right, feels better without a DCHECK.

+  Owner().SetReadyState(is_muted
+                            ? blink::WebMediaStreamSource::kReadyStateMuted
+                            : blink::WebMediaStreamSource::kReadyStateLive);
+}
+
 void MediaStreamSource::SetDeviceInfo(const StreamDeviceInfo& device_info) {
   DCHECK(thread_checker_.CalledOnValidThread());
   device_info_ = device_info;