Change VideoRtpReceiver to create remote VideoTrack and VideoTrackSource.

This enabled us to be able to remove VideoTrack::GetSink and RemoteVideoCapturer.

Since video frames from the decoder is delivered on a media engine internal thread, VideoBroadCaster must be made thread safe.

BUG=webrtc:5426
R=deadbeef@webrtc.org, pthatcher@webrtc.org

Review URL: https://codereview.webrtc.org/1765423005 .

Cr-Commit-Position: refs/heads/master@{#11944}
diff --git a/webrtc/api/api_tests.gyp b/webrtc/api/api_tests.gyp
index 53285f9..bb706dc 100644
--- a/webrtc/api/api_tests.gyp
+++ b/webrtc/api/api_tests.gyp
@@ -37,14 +37,13 @@
         'fakemetricsobserver.h',
         'jsepsessiondescription_unittest.cc',
         'localaudiosource_unittest.cc',
-	'mediaconstraintsinterface_unittest.cc',
+        'mediaconstraintsinterface_unittest.cc',
         'mediastream_unittest.cc',
         'peerconnection_unittest.cc',
         'peerconnectionendtoend_unittest.cc',
         'peerconnectionfactory_unittest.cc',
         'peerconnectioninterface_unittest.cc',
         # 'peerconnectionproxy_unittest.cc',
-        'remotevideocapturer_unittest.cc',
         'rtpsenderreceiver_unittest.cc',
         'statscollector_unittest.cc',
         'test/fakeaudiocapturemodule.cc',
diff --git a/webrtc/api/mediastreaminterface.h b/webrtc/api/mediastreaminterface.h
index 54d3fd4..69a50c9 100644
--- a/webrtc/api/mediastreaminterface.h
+++ b/webrtc/api/mediastreaminterface.h
@@ -177,26 +177,6 @@
 
   virtual VideoTrackSourceInterface* GetSource() const = 0;
 
-  // Return the track input sink. I.e., frames sent to this sink are
-  // propagated to all renderers registered with the track. The
-  // returned sink must not change between calls. Currently, this
-  // method is used for remote tracks (VideoRtpReceiver); further
-  // refactoring is planned for this path, it's unclear if this method
-  // belongs here long term.
-
-  // We do this instead of simply implementing the
-  // VideoSourceInterface directly, because if we did the latter, we'd
-  // need an OnFrame method in VideoTrackProxy, with a thread jump on
-  // each call.
-
-  // TODO(nisse): It has a default implementation so that mock
-  // objects, in particular, chrome's MockWebRtcVideoTrack, doesn't
-  // need to know about it. Consider removing the implementation (or
-  // this comment) after refactoring dust settles.
-  virtual rtc::VideoSinkInterface<cricket::VideoFrame>* GetSink() {
-    return nullptr;
-  };
-
  protected:
   virtual ~VideoTrackInterface() {}
 };
diff --git a/webrtc/api/mediastreamtrackproxy.h b/webrtc/api/mediastreamtrackproxy.h
index ada8291..676ba70 100644
--- a/webrtc/api/mediastreamtrackproxy.h
+++ b/webrtc/api/mediastreamtrackproxy.h
@@ -54,7 +54,6 @@
                 const rtc::VideoSinkWants&)
   PROXY_METHOD1(void, RemoveSink, rtc::VideoSinkInterface<cricket::VideoFrame>*)
   PROXY_CONSTMETHOD0(VideoTrackSourceInterface*, GetSource)
-  PROXY_METHOD0(rtc::VideoSinkInterface<cricket::VideoFrame>*, GetSink)
 
   PROXY_METHOD1(void, RegisterObserver, ObserverInterface*)
   PROXY_METHOD1(void, UnregisterObserver, ObserverInterface*)
diff --git a/webrtc/api/peerconnection.cc b/webrtc/api/peerconnection.cc
index c2039ae..700714a 100644
--- a/webrtc/api/peerconnection.cc
+++ b/webrtc/api/peerconnection.cc
@@ -381,10 +381,8 @@
 // Factory class for creating remote MediaStreams and MediaStreamTracks.
 class RemoteMediaStreamFactory {
  public:
-  explicit RemoteMediaStreamFactory(rtc::Thread* signaling_thread,
-                                    rtc::Thread* worker_thread)
-      : signaling_thread_(signaling_thread),
-        worker_thread_(worker_thread) {}
+  explicit RemoteMediaStreamFactory(rtc::Thread* signaling_thread)
+      : signaling_thread_(signaling_thread) {}
 
   rtc::scoped_refptr<MediaStreamInterface> CreateMediaStream(
       const std::string& stream_label) {
@@ -400,15 +398,6 @@
         stream, track_id, RemoteAudioSource::Create(ssrc, provider));
   }
 
-  VideoTrackInterface* AddVideoTrack(webrtc::MediaStreamInterface* stream,
-                                     const std::string& track_id) {
-    return AddTrack<VideoTrackInterface, VideoTrack, VideoTrackProxy>(
-        stream, track_id,
-        VideoCapturerTrackSource::Create(
-            worker_thread_, new RemoteVideoCapturer(), nullptr, true)
-            .get());
-  }
-
  private:
   template <typename TI, typename T, typename TP, typename S>
   TI* AddTrack(MediaStreamInterface* stream,
@@ -424,7 +413,6 @@
   }
 
   rtc::Thread* signaling_thread_;
-  rtc::Thread* worker_thread_;
 };
 
 bool ExtractMediaSessionOptions(
@@ -611,8 +599,8 @@
 
   media_controller_.reset(factory_->CreateMediaController(media_config));
 
-  remote_stream_factory_.reset(new RemoteMediaStreamFactory(
-      factory_->signaling_thread(), factory_->worker_thread()));
+  remote_stream_factory_.reset(
+      new RemoteMediaStreamFactory(factory_->signaling_thread()));
 
   session_.reset(
       new WebRtcSession(media_controller_.get(), factory_->signaling_thread(),
@@ -1325,11 +1313,12 @@
 }
 
 void PeerConnection::CreateVideoReceiver(MediaStreamInterface* stream,
-                                         VideoTrackInterface* video_track,
+                                         const std::string& track_id,
                                          uint32_t ssrc) {
-  receivers_.push_back(RtpReceiverProxy::Create(
-      signaling_thread(),
-      new VideoRtpReceiver(video_track, ssrc, session_.get())));
+  VideoRtpReceiver* video_receiver = new VideoRtpReceiver(
+      stream, track_id, factory_->worker_thread(), ssrc, session_.get());
+  receivers_.push_back(
+      RtpReceiverProxy::Create(signaling_thread(), video_receiver));
 }
 
 // TODO(deadbeef): Keep RtpReceivers around even if track goes away in remote
@@ -1677,9 +1666,7 @@
         ssrc, session_.get(), stream, track_id);
     CreateAudioReceiver(stream, audio_track, ssrc);
   } else if (media_type == cricket::MEDIA_TYPE_VIDEO) {
-    VideoTrackInterface* video_track =
-        remote_stream_factory_->AddVideoTrack(stream, track_id);
-    CreateVideoReceiver(stream, video_track, ssrc);
+    CreateVideoReceiver(stream, track_id, ssrc);
   } else {
     RTC_DCHECK(false && "Invalid media type");
   }
@@ -1702,8 +1689,9 @@
     rtc::scoped_refptr<VideoTrackInterface> video_track =
         stream->FindVideoTrack(track_id);
     if (video_track) {
-      video_track->set_state(webrtc::MediaStreamTrackInterface::kEnded);
       stream->RemoveTrack(video_track);
+      // Stopping or destroying a VideoRtpReceiver will end the
+      // VideoRtpReceiver::track().
       DestroyVideoReceiver(stream, video_track);
     }
   } else {
diff --git a/webrtc/api/peerconnection.h b/webrtc/api/peerconnection.h
index e4fcdf0..2e9d9b2 100644
--- a/webrtc/api/peerconnection.h
+++ b/webrtc/api/peerconnection.h
@@ -27,6 +27,7 @@
 
 class MediaStreamObserver;
 class RemoteMediaStreamFactory;
+class VideoRtpReceiver;
 
 // Populates |session_options| from |rtc_options|, and returns true if options
 // are valid.
@@ -167,8 +168,9 @@
   void CreateAudioReceiver(MediaStreamInterface* stream,
                            AudioTrackInterface* audio_track,
                            uint32_t ssrc);
+
   void CreateVideoReceiver(MediaStreamInterface* stream,
-                           VideoTrackInterface* video_track,
+                           const std::string& track_id,
                            uint32_t ssrc);
   void DestroyAudioReceiver(MediaStreamInterface* stream,
                             AudioTrackInterface* audio_track);
diff --git a/webrtc/api/remotevideocapturer.cc b/webrtc/api/remotevideocapturer.cc
index 8c1ffcc..177ba54 100644
--- a/webrtc/api/remotevideocapturer.cc
+++ b/webrtc/api/remotevideocapturer.cc
@@ -10,69 +10,4 @@
 
 #include "webrtc/api/remotevideocapturer.h"
 
-#include "webrtc/base/logging.h"
-#include "webrtc/media/base/videoframe.h"
-
-namespace webrtc {
-
-RemoteVideoCapturer::RemoteVideoCapturer() {}
-
-RemoteVideoCapturer::~RemoteVideoCapturer() {}
-
-cricket::CaptureState RemoteVideoCapturer::Start(
-    const cricket::VideoFormat& capture_format) {
-  if (capture_state() == cricket::CS_RUNNING) {
-    LOG(LS_WARNING)
-        << "RemoteVideoCapturer::Start called when it's already started.";
-    return capture_state();
-  }
-
-  LOG(LS_INFO) << "RemoteVideoCapturer::Start";
-  SetCaptureFormat(&capture_format);
-  return cricket::CS_RUNNING;
-}
-
-void RemoteVideoCapturer::Stop() {
-  if (capture_state() == cricket::CS_STOPPED) {
-    LOG(LS_WARNING)
-        << "RemoteVideoCapturer::Stop called when it's already stopped.";
-    return;
-  }
-
-  LOG(LS_INFO) << "RemoteVideoCapturer::Stop";
-  SetCaptureFormat(NULL);
-  SetCaptureState(cricket::CS_STOPPED);
-}
-
-bool RemoteVideoCapturer::IsRunning() {
-  return capture_state() == cricket::CS_RUNNING;
-}
-
-bool RemoteVideoCapturer::GetPreferredFourccs(std::vector<uint32_t>* fourccs) {
-  if (!fourccs)
-    return false;
-  fourccs->push_back(cricket::FOURCC_I420);
-  return true;
-}
-
-bool RemoteVideoCapturer::GetBestCaptureFormat(
-    const cricket::VideoFormat& desired, cricket::VideoFormat* best_format) {
-  if (!best_format) {
-    return false;
-  }
-
-  // RemoteVideoCapturer does not support capability enumeration.
-  // Use the desired format as the best format.
-  best_format->width = desired.width;
-  best_format->height = desired.height;
-  best_format->fourcc = cricket::FOURCC_I420;
-  best_format->interval = desired.interval;
-  return true;
-}
-
-bool RemoteVideoCapturer::IsScreencast() const {
-  // TODO(ronghuawu): what about remote screencast stream.
-  return false;
-}
-
-}  // namespace webrtc
+// TODO(perkj): Remove this file once Chrome gyp file doesn't depend on it.
diff --git a/webrtc/api/remotevideocapturer.h b/webrtc/api/remotevideocapturer.h
index a0fd4b7..774cb5a 100644
--- a/webrtc/api/remotevideocapturer.h
+++ b/webrtc/api/remotevideocapturer.h
@@ -11,38 +11,6 @@
 #ifndef WEBRTC_API_REMOTEVIDEOCAPTURER_H_
 #define WEBRTC_API_REMOTEVIDEOCAPTURER_H_
 
-#include <vector>
-
-#include "webrtc/api/mediastreaminterface.h"
-#include "webrtc/media/base/videocapturer.h"
-#include "webrtc/media/base/videorenderer.h"
-
-namespace webrtc {
-
-// RemoteVideoCapturer implements a simple cricket::VideoCapturer which
-// gets decoded remote video frames from media channel.
-// It's used as the remote video source's VideoCapturer so that the remote video
-// can be used as a cricket::VideoCapturer and in that way a remote video stream
-// can implement the MediaStreamSourceInterface.
-class RemoteVideoCapturer : public cricket::VideoCapturer {
- public:
-  RemoteVideoCapturer();
-  virtual ~RemoteVideoCapturer();
-
-  // cricket::VideoCapturer implementation.
-  cricket::CaptureState Start(
-      const cricket::VideoFormat& capture_format) override;
-  void Stop() override;
-  bool IsRunning() override;
-  bool GetPreferredFourccs(std::vector<uint32_t>* fourccs) override;
-  bool GetBestCaptureFormat(const cricket::VideoFormat& desired,
-                            cricket::VideoFormat* best_format) override;
-  bool IsScreencast() const override;
-
- private:
-  RTC_DISALLOW_COPY_AND_ASSIGN(RemoteVideoCapturer);
-};
-
-}  // namespace webrtc
+// TODO(perkj): Remove this file once Chrome gyp file doesn't depend on it.
 
 #endif  // WEBRTC_API_REMOTEVIDEOCAPTURER_H_
diff --git a/webrtc/api/remotevideocapturer_unittest.cc b/webrtc/api/remotevideocapturer_unittest.cc
deleted file mode 100644
index 6478d21..0000000
--- a/webrtc/api/remotevideocapturer_unittest.cc
+++ /dev/null
@@ -1,97 +0,0 @@
-/*
- *  Copyright 2013 The WebRTC project authors. All Rights Reserved.
- *
- *  Use of this source code is governed by a BSD-style license
- *  that can be found in the LICENSE file in the root of the source
- *  tree. An additional intellectual property rights grant can be found
- *  in the file PATENTS.  All contributing project authors may
- *  be found in the AUTHORS file in the root of the source tree.
- */
-
-#include <string>
-
-#include "webrtc/api/remotevideocapturer.h"
-#include "webrtc/base/gunit.h"
-#include "webrtc/media/engine/webrtcvideoframe.h"
-
-using cricket::CaptureState;
-using cricket::VideoCapturer;
-using cricket::VideoFormat;
-using cricket::VideoFormatPod;
-using cricket::VideoFrame;
-
-static const int kMaxWaitMs = 1000;
-static const VideoFormatPod kTestFormat =
-    {640, 480, FPS_TO_INTERVAL(30), cricket::FOURCC_ANY};
-
-class RemoteVideoCapturerTest : public testing::Test,
-                                public sigslot::has_slots<> {
- protected:
-  RemoteVideoCapturerTest()
-      : captured_frame_num_(0),
-        capture_state_(cricket::CS_STOPPED) {}
-
-  virtual void SetUp() {
-    capturer_.SignalStateChange.connect(
-        this, &RemoteVideoCapturerTest::OnStateChange);
-  }
-
-  ~RemoteVideoCapturerTest() {
-    capturer_.SignalStateChange.disconnect(this);
-  }
-
-  int captured_frame_num() const {
-    return captured_frame_num_;
-  }
-
-  CaptureState capture_state() const {
-    return capture_state_;
-  }
-
-  webrtc::RemoteVideoCapturer capturer_;
-
- private:
-  void OnStateChange(VideoCapturer* capturer,
-                     CaptureState capture_state) {
-    EXPECT_EQ(&capturer_, capturer);
-    capture_state_ = capture_state;
-  }
-
-  int captured_frame_num_;
-  CaptureState capture_state_;
-};
-
-TEST_F(RemoteVideoCapturerTest, StartStop) {
-  // Start
-  EXPECT_TRUE(
-      capturer_.StartCapturing(VideoFormat(kTestFormat)));
-  EXPECT_TRUE_WAIT((cricket::CS_RUNNING == capture_state()), kMaxWaitMs);
-  EXPECT_EQ(VideoFormat(kTestFormat),
-            *capturer_.GetCaptureFormat());
-  EXPECT_TRUE(capturer_.IsRunning());
-
-  // Stop
-  capturer_.Stop();
-  EXPECT_TRUE_WAIT((cricket::CS_STOPPED == capture_state()), kMaxWaitMs);
-  EXPECT_TRUE(NULL == capturer_.GetCaptureFormat());
-}
-
-TEST_F(RemoteVideoCapturerTest, GetPreferredFourccs) {
-  EXPECT_FALSE(capturer_.GetPreferredFourccs(NULL));
-
-  std::vector<uint32_t> fourccs;
-  EXPECT_TRUE(capturer_.GetPreferredFourccs(&fourccs));
-  EXPECT_EQ(1u, fourccs.size());
-  EXPECT_EQ(cricket::FOURCC_I420, fourccs.at(0));
-}
-
-TEST_F(RemoteVideoCapturerTest, GetBestCaptureFormat) {
-  VideoFormat desired = VideoFormat(kTestFormat);
-  EXPECT_FALSE(capturer_.GetBestCaptureFormat(desired, NULL));
-
-  VideoFormat expected_format = VideoFormat(kTestFormat);
-  expected_format.fourcc = cricket::FOURCC_I420;
-  VideoFormat best_format;
-  EXPECT_TRUE(capturer_.GetBestCaptureFormat(desired, &best_format));
-  EXPECT_EQ(expected_format, best_format);
-}
diff --git a/webrtc/api/rtpreceiver.cc b/webrtc/api/rtpreceiver.cc
index 0ad5218..1590612 100644
--- a/webrtc/api/rtpreceiver.cc
+++ b/webrtc/api/rtpreceiver.cc
@@ -10,7 +10,8 @@
 
 #include "webrtc/api/rtpreceiver.h"
 
-#include "webrtc/api/videosourceinterface.h"
+#include "webrtc/api/mediastreamtrackproxy.h"
+#include "webrtc/api/videotrack.h"
 
 namespace webrtc {
 
@@ -65,11 +66,27 @@
   provider_->SetAudioPlayout(ssrc_, track_->enabled());
 }
 
-VideoRtpReceiver::VideoRtpReceiver(VideoTrackInterface* track,
+VideoRtpReceiver::VideoRtpReceiver(MediaStreamInterface* stream,
+                                   const std::string& track_id,
+                                   rtc::Thread* worker_thread,
                                    uint32_t ssrc,
                                    VideoProviderInterface* provider)
-    : id_(track->id()), track_(track), ssrc_(ssrc), provider_(provider) {
-  provider_->SetVideoPlayout(ssrc_, true, track_->GetSink());
+    : id_(track_id),
+      ssrc_(ssrc),
+      provider_(provider),
+      source_(new RefCountedObject<VideoTrackSource>(&broadcaster_,
+                                                     worker_thread,
+                                                     true /* remote */)),
+      track_(VideoTrackProxy::Create(
+          rtc::Thread::Current(),
+          VideoTrack::Create(track_id, source_.get()))) {
+  source_->SetState(MediaSourceInterface::kLive);
+  // TODO(perkj): It should be enough to set the source state. All tracks
+  // belonging to the same source should get its state from the source.
+  // I.e. if a track has been cloned from a remote source.
+  track_->set_state(webrtc::MediaStreamTrackInterface::kLive);
+  provider_->SetVideoPlayout(ssrc_, true, &broadcaster_);
+  stream->AddTrack(track_);
 }
 
 VideoRtpReceiver::~VideoRtpReceiver() {
@@ -83,6 +100,11 @@
   if (!provider_) {
     return;
   }
+  source_->SetState(MediaSourceInterface::kEnded);
+  source_->OnSourceDestroyed();
+  // TODO(perkj): It should be enough to set the source state. All tracks
+  // belonging to the same source should get its state from the source.
+  track_->set_state(MediaStreamTrackInterface::kEnded);
   provider_->SetVideoPlayout(ssrc_, false, nullptr);
   provider_ = nullptr;
 }
diff --git a/webrtc/api/rtpreceiver.h b/webrtc/api/rtpreceiver.h
index 43adc72..a62ed19 100644
--- a/webrtc/api/rtpreceiver.h
+++ b/webrtc/api/rtpreceiver.h
@@ -19,7 +19,9 @@
 
 #include "webrtc/api/mediastreamprovider.h"
 #include "webrtc/api/rtpreceiverinterface.h"
+#include "webrtc/api/videotracksource.h"
 #include "webrtc/base/basictypes.h"
+#include "webrtc/media/base/videobroadcaster.h"
 
 namespace webrtc {
 
@@ -60,12 +62,18 @@
 
 class VideoRtpReceiver : public rtc::RefCountedObject<RtpReceiverInterface> {
  public:
-  VideoRtpReceiver(VideoTrackInterface* track,
+  VideoRtpReceiver(MediaStreamInterface* stream,
+                   const std::string& track_id,
+                   rtc::Thread* worker_thread,
                    uint32_t ssrc,
                    VideoProviderInterface* provider);
 
   virtual ~VideoRtpReceiver();
 
+  rtc::scoped_refptr<VideoTrackInterface> video_track() const {
+    return track_.get();
+  }
+
   // RtpReceiverInterface implementation
   rtc::scoped_refptr<MediaStreamTrackInterface> track() const override {
     return track_.get();
@@ -77,9 +85,16 @@
 
  private:
   std::string id_;
-  rtc::scoped_refptr<VideoTrackInterface> track_;
   uint32_t ssrc_;
   VideoProviderInterface* provider_;
+  // |broadcaster_| is needed since the decoder can only handle one sink.
+  // It might be better if the decoder can handle multiple sinks and consider
+  // the VideoSinkWants.
+  rtc::VideoBroadcaster broadcaster_;
+  // |source_| is held here to be able to change the state of the source when
+  // the VideoRtpReceiver is stopped.
+  rtc::scoped_refptr<VideoTrackSource> source_;
+  rtc::scoped_refptr<VideoTrackInterface> track_;
 };
 
 }  // namespace webrtc
diff --git a/webrtc/api/rtpsenderreceiver_unittest.cc b/webrtc/api/rtpsenderreceiver_unittest.cc
index 0a7c408..22fa14f 100644
--- a/webrtc/api/rtpsenderreceiver_unittest.cc
+++ b/webrtc/api/rtpsenderreceiver_unittest.cc
@@ -150,12 +150,11 @@
   }
 
   void CreateVideoRtpReceiver() {
-    AddVideoTrack(true);
-    EXPECT_CALL(video_provider_,
-                SetVideoPlayout(kVideoSsrc, true,
-                                video_track_->GetSink()));
-    video_rtp_receiver_ = new VideoRtpReceiver(stream_->GetVideoTracks()[0],
-                                               kVideoSsrc, &video_provider_);
+    EXPECT_CALL(video_provider_, SetVideoPlayout(kVideoSsrc, true, _));
+    video_rtp_receiver_ =
+        new VideoRtpReceiver(stream_, kVideoTrackId, rtc::Thread::Current(),
+                             kVideoSsrc, &video_provider_);
+    video_track_ = video_rtp_receiver_->video_track();
   }
 
   void DestroyAudioRtpReceiver() {
@@ -244,6 +243,20 @@
   DestroyVideoRtpSender();
 }
 
+TEST_F(RtpSenderReceiverTest, RemoteVideoTrackState) {
+  CreateVideoRtpReceiver();
+
+  EXPECT_EQ(webrtc::MediaStreamTrackInterface::kLive, video_track_->state());
+  EXPECT_EQ(webrtc::MediaSourceInterface::kLive,
+            video_track_->GetSource()->state());
+
+  DestroyVideoRtpReceiver();
+
+  EXPECT_EQ(webrtc::MediaStreamTrackInterface::kEnded, video_track_->state());
+  EXPECT_EQ(webrtc::MediaSourceInterface::kEnded,
+            video_track_->GetSource()->state());
+}
+
 TEST_F(RtpSenderReceiverTest, RemoteVideoTrackDisable) {
   CreateVideoRtpReceiver();
 
diff --git a/webrtc/api/videocapturertracksource_unittest.cc b/webrtc/api/videocapturertracksource_unittest.cc
index b183421..0a06870 100644
--- a/webrtc/api/videocapturertracksource_unittest.cc
+++ b/webrtc/api/videocapturertracksource_unittest.cc
@@ -182,27 +182,6 @@
   source_->Stop();
 }
 
-// Test start stop with a remote VideoSource - the video source that has a
-// RemoteVideoCapturer and takes video frames from FrameInput.
-TEST_F(VideoCapturerTrackSourceTest, StartStopRemote) {
-  source_ = VideoCapturerTrackSource::Create(
-      rtc::Thread::Current(), new webrtc::RemoteVideoCapturer(), NULL, true);
-
-  ASSERT_TRUE(source_.get() != NULL);
-  EXPECT_TRUE(NULL != source_->GetVideoCapturer());
-
-  state_observer_.reset(new StateObserver(source_));
-  source_->RegisterObserver(state_observer_.get());
-  source_->AddOrUpdateSink(&renderer_, rtc::VideoSinkWants());
-
-  EXPECT_EQ_WAIT(MediaSourceInterface::kLive, state_observer_->state(),
-                 kMaxWaitMs);
-
-  source_->GetVideoCapturer()->Stop();
-  EXPECT_EQ_WAIT(MediaSourceInterface::kEnded, state_observer_->state(),
-                 kMaxWaitMs);
-}
-
 // Test that a VideoSource transition to kEnded if the capture device
 // fails.
 TEST_F(VideoCapturerTrackSourceTest, CameraFailed) {
diff --git a/webrtc/api/videotrack.cc b/webrtc/api/videotrack.cc
index 36d256f..b2ea1f9 100644
--- a/webrtc/api/videotrack.cc
+++ b/webrtc/api/videotrack.cc
@@ -50,10 +50,6 @@
   renderers_.RemoveSink(sink);
 }
 
-rtc::VideoSinkInterface<cricket::VideoFrame>* VideoTrack::GetSink() {
-  return &renderers_;
-}
-
 bool VideoTrack::set_enabled(bool enable) {
   renderers_.SetEnabled(enable);
   return MediaStreamTrack<VideoTrackInterface>::set_enabled(enable);
diff --git a/webrtc/api/videotrack.h b/webrtc/api/videotrack.h
index 066aa90..3a59504 100644
--- a/webrtc/api/videotrack.h
+++ b/webrtc/api/videotrack.h
@@ -33,7 +33,6 @@
   virtual VideoTrackSourceInterface* GetSource() const {
     return video_source_.get();
   }
-  rtc::VideoSinkInterface<cricket::VideoFrame>* GetSink() override;
   virtual bool set_enabled(bool enable);
   virtual std::string kind() const;
 
diff --git a/webrtc/api/videotrack_unittest.cc b/webrtc/api/videotrack_unittest.cc
index 9f44b81..008ba21 100644
--- a/webrtc/api/videotrack_unittest.cc
+++ b/webrtc/api/videotrack_unittest.cc
@@ -10,42 +10,37 @@
 
 #include <string>
 
-#include "webrtc/api/remotevideocapturer.h"
 #include "webrtc/api/test/fakevideotrackrenderer.h"
 #include "webrtc/api/videocapturertracksource.h"
 #include "webrtc/api/videotrack.h"
 #include "webrtc/base/gunit.h"
 #include "webrtc/base/scoped_ptr.h"
+#include "webrtc/media/base/fakevideocapturer.h"
 #include "webrtc/media/base/fakemediaengine.h"
 #include "webrtc/media/engine/webrtcvideoframe.h"
-#include "webrtc/pc/channelmanager.h"
 
 using webrtc::FakeVideoTrackRenderer;
 using webrtc::FakeVideoTrackRendererOld;
-using webrtc::VideoCapturerTrackSource;
+using webrtc::VideoTrackSource;
 using webrtc::VideoTrack;
 using webrtc::VideoTrackInterface;
 
-namespace {
-
-class WebRtcVideoTestFrame : public cricket::WebRtcVideoFrame {
- public:
-  using cricket::WebRtcVideoFrame::SetRotation;
-};
-
-}  // namespace
 
 class VideoTrackTest : public testing::Test {
  public:
   VideoTrackTest() {
     static const char kVideoTrackId[] = "track_id";
     video_track_ = VideoTrack::Create(
-        kVideoTrackId, VideoCapturerTrackSource::Create(
-                           rtc::Thread::Current(),
-                           new webrtc::RemoteVideoCapturer(), NULL, true));
+        kVideoTrackId,
+        new rtc::RefCountedObject<VideoTrackSource>(
+            &capturer_, rtc::Thread::Current(), true /* remote */));
+    capturer_.Start(
+        cricket::VideoFormat(640, 480, cricket::VideoFormat::FpsToInterval(30),
+                             cricket::FOURCC_I420));
   }
 
  protected:
+  cricket::FakeVideoCapturer capturer_;
   rtc::scoped_refptr<VideoTrackInterface> video_track_;
 };
 
@@ -56,35 +51,18 @@
   rtc::scoped_ptr<FakeVideoTrackRenderer> renderer_1(
       new FakeVideoTrackRenderer(video_track_.get()));
 
-  rtc::VideoSinkInterface<cricket::VideoFrame>* renderer_input =
-      video_track_->GetSink();
-  ASSERT_FALSE(renderer_input == NULL);
-
-  cricket::WebRtcVideoFrame frame;
-  frame.InitToBlack(123, 123, 0);
-  renderer_input->OnFrame(frame);
+  capturer_.CaptureFrame();
   EXPECT_EQ(1, renderer_1->num_rendered_frames());
 
-  EXPECT_EQ(123, renderer_1->width());
-  EXPECT_EQ(123, renderer_1->height());
-
   // FakeVideoTrackRenderer register itself to |video_track_|
   rtc::scoped_ptr<FakeVideoTrackRenderer> renderer_2(
       new FakeVideoTrackRenderer(video_track_.get()));
-
-  renderer_input->OnFrame(frame);
-
-  EXPECT_EQ(123, renderer_1->width());
-  EXPECT_EQ(123, renderer_1->height());
-  EXPECT_EQ(123, renderer_2->width());
-  EXPECT_EQ(123, renderer_2->height());
-
+  capturer_.CaptureFrame();
   EXPECT_EQ(2, renderer_1->num_rendered_frames());
   EXPECT_EQ(1, renderer_2->num_rendered_frames());
 
   video_track_->RemoveSink(renderer_1.get());
-  renderer_input->OnFrame(frame);
-
+  capturer_.CaptureFrame();
   EXPECT_EQ(2, renderer_1->num_rendered_frames());
   EXPECT_EQ(2, renderer_2->num_rendered_frames());
 }
@@ -97,35 +75,19 @@
   rtc::scoped_ptr<FakeVideoTrackRendererOld> renderer_1(
       new FakeVideoTrackRendererOld(video_track_.get()));
 
-  rtc::VideoSinkInterface<cricket::VideoFrame>* renderer_input =
-      video_track_->GetSink();
-  ASSERT_FALSE(renderer_input == NULL);
-
-  cricket::WebRtcVideoFrame frame;
-  frame.InitToBlack(123, 123, 0);
-  renderer_input->OnFrame(frame);
+  capturer_.CaptureFrame();
   EXPECT_EQ(1, renderer_1->num_rendered_frames());
 
-  EXPECT_EQ(123, renderer_1->width());
-  EXPECT_EQ(123, renderer_1->height());
-
   // FakeVideoTrackRenderer register itself to |video_track_|
   rtc::scoped_ptr<FakeVideoTrackRenderer> renderer_2(
       new FakeVideoTrackRenderer(video_track_.get()));
 
-  renderer_input->OnFrame(frame);
-
-  EXPECT_EQ(123, renderer_1->width());
-  EXPECT_EQ(123, renderer_1->height());
-  EXPECT_EQ(123, renderer_2->width());
-  EXPECT_EQ(123, renderer_2->height());
-
+  capturer_.CaptureFrame();
   EXPECT_EQ(2, renderer_1->num_rendered_frames());
   EXPECT_EQ(1, renderer_2->num_rendered_frames());
 
   video_track_->RemoveRenderer(renderer_1.get());
-  renderer_input->OnFrame(frame);
-
+  capturer_.CaptureFrame();
   EXPECT_EQ(2, renderer_1->num_rendered_frames());
   EXPECT_EQ(2, renderer_2->num_rendered_frames());
 }
@@ -135,32 +97,17 @@
   rtc::scoped_ptr<FakeVideoTrackRenderer> renderer(
       new FakeVideoTrackRenderer(video_track_.get()));
 
-  rtc::VideoSinkInterface<cricket::VideoFrame>* renderer_input =
-      video_track_->GetSink();
-  ASSERT_FALSE(renderer_input == NULL);
-
-  cricket::WebRtcVideoFrame frame;
-  frame.InitToBlack(100, 200, 0);
-  // Make it not all-black
-  frame.GetUPlane()[0] = 0;
-
-  renderer_input->OnFrame(frame);
+  capturer_.CaptureFrame();
   EXPECT_EQ(1, renderer->num_rendered_frames());
   EXPECT_FALSE(renderer->black_frame());
-  EXPECT_EQ(100, renderer->width());
-  EXPECT_EQ(200, renderer->height());
 
   video_track_->set_enabled(false);
-  renderer_input->OnFrame(frame);
+  capturer_.CaptureFrame();
   EXPECT_EQ(2, renderer->num_rendered_frames());
   EXPECT_TRUE(renderer->black_frame());
-  EXPECT_EQ(100, renderer->width());
-  EXPECT_EQ(200, renderer->height());
 
   video_track_->set_enabled(true);
-  renderer_input->OnFrame(frame);
+  capturer_.CaptureFrame();
   EXPECT_EQ(3, renderer->num_rendered_frames());
   EXPECT_FALSE(renderer->black_frame());
-  EXPECT_EQ(100, renderer->width());
-  EXPECT_EQ(200, renderer->height());
 }
diff --git a/webrtc/api/videotracksource.cc b/webrtc/api/videotracksource.cc
index 3b5e19a..f8212d7 100644
--- a/webrtc/api/videotracksource.cc
+++ b/webrtc/api/videotracksource.cc
@@ -32,9 +32,16 @@
   }
 }
 
+void VideoTrackSource::OnSourceDestroyed() {
+  source_ = nullptr;
+}
+
 void VideoTrackSource::AddOrUpdateSink(
     rtc::VideoSinkInterface<cricket::VideoFrame>* sink,
     const rtc::VideoSinkWants& wants) {
+  if (!source_) {
+    return;
+  }
   worker_thread_->Invoke<void>(rtc::Bind(
       &rtc::VideoSourceInterface<cricket::VideoFrame>::AddOrUpdateSink, source_,
       sink, wants));
@@ -42,6 +49,9 @@
 
 void VideoTrackSource::RemoveSink(
     rtc::VideoSinkInterface<cricket::VideoFrame>* sink) {
+  if (!source_) {
+    return;
+  }
   worker_thread_->Invoke<void>(
       rtc::Bind(&rtc::VideoSourceInterface<cricket::VideoFrame>::RemoveSink,
                 source_, sink));
diff --git a/webrtc/api/videotracksource.h b/webrtc/api/videotracksource.h
index 59dae42..5e2437c 100644
--- a/webrtc/api/videotracksource.h
+++ b/webrtc/api/videotracksource.h
@@ -24,21 +24,27 @@
   VideoTrackSource(rtc::VideoSourceInterface<cricket::VideoFrame>* source,
                    rtc::Thread* worker_thread,
                    bool remote);
-
   void SetState(SourceState new_state);
+  // OnSourceDestroyed clears this instance pointer to |source_|. It is useful
+  // when the underlying rtc::VideoSourceInterface is destroyed before the
+  // reference counted VideoTrackSource.
+  void OnSourceDestroyed();
+
   SourceState state() const override { return state_; }
   bool remote() const override { return remote_; }
 
   void Stop() override{};
   void Restart() override{};
 
-  virtual bool is_screencast() const { return false; };
-  virtual bool needs_denoising() const { return false; };
+  virtual bool is_screencast() const { return false; }
+  virtual bool needs_denoising() const { return false; }
 
   void AddOrUpdateSink(rtc::VideoSinkInterface<cricket::VideoFrame>* sink,
                        const rtc::VideoSinkWants& wants) override;
   void RemoveSink(rtc::VideoSinkInterface<cricket::VideoFrame>* sink) override;
 
+  cricket::VideoCapturer* GetVideoCapturer() override { return nullptr; }
+
  protected:
   rtc::Thread* worker_thread() { return worker_thread_; }