From 71c232e8df105dd00c006d96ea227329337c66af Mon Sep 17 00:00:00 2001
From: Andreas Pehrson <apehrson@mozilla.com>
Date: Wed, 19 Aug 2020 22:18:37 +0000
Subject: [PATCH] Bug 1652884 - Make MediaPipelineTransmit listen for track
 enabled state changes from the graph. r=jib

Previously it listened for them on main thread, as notified by the
MediaStreamTrack it was transmitting directly. With this patch it
listens for them through the TrackListener in the graph, and will
get notified when any track prior to the MediaStreamTrack's main
track in the graph changes enabled state as well.

Depends on D86926.

Differential Revision: https://phabricator.services.mozilla.com/D86931
---
 .../src/mediapipeline/MediaPipeline.cpp       | 51 +++----------------
 .../src/mediapipeline/MediaPipeline.h         |  4 --
 2 files changed, 6 insertions(+), 49 deletions(-)

diff --git a/media/webrtc/signaling/src/mediapipeline/MediaPipeline.cpp b/media/webrtc/signaling/src/mediapipeline/MediaPipeline.cpp
index 03a631461afc..395005b6eafa 100644
--- a/media/webrtc/signaling/src/mediapipeline/MediaPipeline.cpp
+++ b/media/webrtc/signaling/src/mediapipeline/MediaPipeline.cpp
@@ -724,11 +724,11 @@ class MediaPipelineTransmit::PipelineListener
         ->SendVideoFrame(aVideoFrame);
   }
 
-  void SetTrackEnabled(MediaStreamTrack* aTrack, bool aEnabled);
-
   // Implement MediaTrackListener
   void NotifyQueuedChanges(MediaTrackGraph* aGraph, TrackTime aOffset,
                            const MediaSegment& aQueuedMedia) override;
+  void NotifyEnabledStateChanged(MediaTrackGraph* aGraph,
+                                 bool aEnabled) override;
 
   // Implement DirectMediaTrackListener
   void NotifyRealtimeTrackData(MediaTrackGraph* aGraph, TrackTime aOffset,
@@ -753,29 +753,6 @@ class MediaPipelineTransmit::PipelineListener
   bool mDirectConnect;
 };
 
-// MediaStreamTrackConsumer inherits from SupportsWeakPtr, which is
-// main-thread-only.
-class MediaPipelineTransmit::PipelineListenerTrackConsumer
-    : public MediaStreamTrackConsumer {
-  virtual ~PipelineListenerTrackConsumer() { MOZ_ASSERT(NS_IsMainThread()); }
-
-  const RefPtr<PipelineListener> mListener;
-
- public:
-  NS_INLINE_DECL_REFCOUNTING(PipelineListenerTrackConsumer)
-
-  explicit PipelineListenerTrackConsumer(RefPtr<PipelineListener> aListener)
-      : mListener(std::move(aListener)) {
-    MOZ_ASSERT(NS_IsMainThread());
-  }
-
-  // Implement MediaStreamTrackConsumer
-  void NotifyEnabledChanged(MediaStreamTrack* aTrack, bool aEnabled) override {
-    MOZ_ASSERT(NS_IsMainThread());
-    mListener->SetTrackEnabled(aTrack, aEnabled);
-  }
-};
-
 // Implements VideoConverterListener for MediaPipeline.
 //
 // We pass converted frames on to MediaPipelineTransmit::PipelineListener
@@ -822,10 +799,6 @@ MediaPipelineTransmit::MediaPipelineTransmit(
                     std::move(aConduit)),
       mIsVideo(aIsVideo),
       mListener(new PipelineListener(mConduit)),
-      mTrackConsumer(
-          MakeAndAddRef<nsMainThreadPtrHolder<PipelineListenerTrackConsumer>>(
-              "MediaPipelineTransmit::mTrackConsumer",
-              MakeAndAddRef<PipelineListenerTrackConsumer>(mListener))),
       mFeeder(aIsVideo ? MakeAndAddRef<VideoFrameFeeder>(mListener)
                        : nullptr),  // For video we send frames to an
                                     // async VideoFrameConverter that
@@ -935,10 +908,10 @@ void MediaPipelineTransmit::Start() {
 
   mSendTrack->Resume();
 
+  mSendTrack->AddListener(mListener);
   if (mSendTrack->mType == MediaSegment::VIDEO) {
     mSendTrack->AddDirectListener(mListener);
   }
-  mSendTrack->AddListener(mListener);
 }
 
 bool MediaPipelineTransmit::IsVideo() const { return mIsVideo; }
@@ -978,10 +951,7 @@ void MediaPipelineTransmit::UpdateSinkIdentity_m(
 void MediaPipelineTransmit::DetachMedia() {
   ASSERT_ON_THREAD(mMainThread);
   MOZ_ASSERT(!mTransmitting);
-  if (mDomTrack) {
-    mDomTrack->RemoveConsumer(mTrackConsumer);
-    mDomTrack = nullptr;
-  }
+  mDomTrack = nullptr;
   if (mSendPort) {
     mSendPort->Destroy();
     mSendPort = nullptr;
@@ -1036,9 +1006,6 @@ nsresult MediaPipelineTransmit::SetTrack(RefPtr<MediaStreamTrack> aDomTrack) {
          (mConduit->type() == MediaSessionConduit::AUDIO ? "audio" : "video")));
   }
 
-  if (mDomTrack) {
-    mDomTrack->RemoveConsumer(mTrackConsumer);
-  }
   if (mSendPort) {
     mSendPort->Destroy();
     mSendPort = nullptr;
@@ -1076,10 +1043,6 @@ nsresult MediaPipelineTransmit::SetTrack(RefPtr<MediaStreamTrack> aDomTrack) {
       }
       mSendPort = mSendTrack->AllocateInputPort(mDomTrack->GetTrack());
     }
-    mDomTrack->AddConsumer(mTrackConsumer);
-    if (mConverter) {
-      mConverter->SetTrackEnabled(mDomTrack->Enabled());
-    }
   }
 
   return NS_OK;
@@ -1210,13 +1173,11 @@ void MediaPipelineTransmit::PipelineListener::NotifyQueuedChanges(
   NewData(aQueuedMedia, rate);
 }
 
-void MediaPipelineTransmit::PipelineListener::SetTrackEnabled(
-    MediaStreamTrack* aTrack, bool aEnabled) {
-  MOZ_ASSERT(NS_IsMainThread());
+void MediaPipelineTransmit::PipelineListener::NotifyEnabledStateChanged(
+    MediaTrackGraph* aGraph, bool aEnabled) {
   if (mConduit->type() != MediaSessionConduit::VIDEO) {
     return;
   }
-
   MOZ_ASSERT(mConverter);
   mConverter->SetTrackEnabled(aEnabled);
 }
diff --git a/media/webrtc/signaling/src/mediapipeline/MediaPipeline.h b/media/webrtc/signaling/src/mediapipeline/MediaPipeline.h
index b6d687125f8b..484a4431cec7 100644
--- a/media/webrtc/signaling/src/mediapipeline/MediaPipeline.h
+++ b/media/webrtc/signaling/src/mediapipeline/MediaPipeline.h
@@ -310,7 +310,6 @@ class MediaPipelineTransmit : public MediaPipeline {
 
   // Separate classes to allow ref counting
   class PipelineListener;
-  class PipelineListenerTrackConsumer;
   class VideoFrameFeeder;
 
  protected:
@@ -323,9 +322,6 @@ class MediaPipelineTransmit : public MediaPipeline {
 
   const bool mIsVideo;
   const RefPtr<PipelineListener> mListener;
-  // Listens for changes in enabled state on the attached MediaStreamTrack, and
-  // notifies mListener.
-  const nsMainThreadPtrHandle<PipelineListenerTrackConsumer> mTrackConsumer;
   const RefPtr<VideoFrameFeeder> mFeeder;
   RefPtr<AudioProxyThread> mAudioProcessing;
   RefPtr<VideoFrameConverter> mConverter;