Propagate muted state from MediaStreamAudioSource into JS.

third_party/WebKit/Source/modules/mediastream/MediaStreamTrack.cpp

Index: third_party/WebKit/Source/modules/mediastream/MediaStreamTrack.cpp
diff --git a/third_party/WebKit/Source/modules/mediastream/MediaStreamTrack.cpp b/third_party/WebKit/Source/modules/mediastream/MediaStreamTrack.cpp
index 023f078fd0e020bfc961d058afe748eba410c11a..f2b44ad1e7e921be4ba8d246d69043a2a2ea44c1 100644
--- a/third_party/WebKit/Source/modules/mediastream/MediaStreamTrack.cpp
+++ b/third_party/WebKit/Source/modules/mediastream/MediaStreamTrack.cpp
@@ -64,7 +64,7 @@ MediaStreamTrack* MediaStreamTrack::Create(ExecutionContext* context,
 MediaStreamTrack::MediaStreamTrack(ExecutionContext* context,
                                    MediaStreamComponent* component)
     : ContextLifecycleObserver(context),
-      ready_state_(MediaStreamSource::kReadyStateLive),
+      ready_state_(component->Source()->GetReadyState()),
       is_iterating_registered_media_streams_(false),
       stopped_(false),
       component_(component),
@@ -72,6 +72,11 @@ MediaStreamTrack::MediaStreamTrack(ExecutionContext* context,
       constraints_() {
   component_->Source()->AddObserver(this);
 
+  // If the source is already non-live at this point, the observer won't have
+  // been called. Check the muted state manually.
+  if (ready_state_ == MediaStreamSource::kReadyStateMuted)

[miu, 2017/06/19 19:40:37]

This code assumes MediaStreamComponent::muted_ is always false at this point.
However, this is not guaranteed (see the MSC ctor).

Suggest making this an unconditional call:

  component_->SetMuted(ready_state_ == MediaStreamSource::kReadyStateMuted);

[ossu-chromium, 2017/06/26 16:06:14]

From what I could gather, that constructor is (un?)fortunately never called with
muted set to anything but false. However, I think your suggestion makes a lot of
sense. Will change!

+    component_->SetMuted(true);
+
   if (component_->Source() &&
       component_->Source()->GetType() == MediaStreamSource::kTypeVideo) {
     // ImageCapture::create() only throws if |this| track is not of video type.
@@ -183,11 +188,12 @@ String MediaStreamTrack::readyState() const {
   if (Ended())
     return "ended";
 
+  // Although muted is tracked as a ReadyState, only "live" and "ended" are
+  // visible externally.
   switch (ready_state_) {
     case MediaStreamSource::kReadyStateLive:
-      return "live";
     case MediaStreamSource::kReadyStateMuted:
-      return "muted";
+      return "live";
     case MediaStreamSource::kReadyStateEnded:
       return "ended";
   }