Adding upstream version 1:115.7.0.upstream/1%115.7.0upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

14 files changed, 1876 insertions, 0 deletions

diff --git a/third_party/libwebrtc/test/peer_scenario/BUILD.gn b/third_party/libwebrtc/test/peer_scenario/BUILD.gn
new file mode 100644
index 0000000000..00492a18a9
--- /dev/null
+++ b/third_party/libwebrtc/test/peer_scenario/BUILD.gn
@@ -0,0 +1,68 @@
+# Copyright (c) 2019 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.
+
+import("../../webrtc.gni")
+
+if (rtc_include_tests) {
+  rtc_library("peer_scenario") {
+    testonly = true
+    sources = [
+      "peer_scenario.cc",
+      "peer_scenario.h",
+      "peer_scenario_client.cc",
+      "peer_scenario_client.h",
+      "scenario_connection.cc",
+      "scenario_connection.h",
+      "signaling_route.cc",
+      "signaling_route.h",
+    ]
+    deps = [
+      "..:fake_video_codecs",
+      "..:fileutils",
+      "..:test_support",
+      "../:video_test_common",
+      "../../api:candidate",
+      "../../api:create_time_controller",
+      "../../api:libjingle_peerconnection_api",
+      "../../api:network_emulation_manager_api",
+      "../../api:rtc_stats_api",
+      "../../api:time_controller",
+      "../../api/audio_codecs:builtin_audio_decoder_factory",
+      "../../api/audio_codecs:builtin_audio_encoder_factory",
+      "../../api/rtc_event_log:rtc_event_log_factory",
+      "../../api/task_queue:default_task_queue_factory",
+      "../../api/transport:field_trial_based_config",
+      "../../api/video_codecs:builtin_video_decoder_factory",
+      "../../api/video_codecs:builtin_video_encoder_factory",
+      "../../media:rtc_audio_video",
+      "../../media:rtc_media_base",
+      "../../media:rtp_utils",
+      "../../modules/audio_device:audio_device_impl",
+      "../../modules/rtp_rtcp:rtp_rtcp_format",
+      "../../p2p:rtc_p2p",
+      "../../pc:channel",
+      "../../pc:jsep_transport_controller",
+      "../../pc:pc_test_utils",
+      "../../pc:rtp_transport_internal",
+      "../../pc:session_description",
+      "../../rtc_base:null_socket_server",
+      "../../rtc_base:stringutils",
+      "../../rtc_base:task_queue_for_test",
+      "../../test:explicit_key_value_config",
+      "../../test:scoped_key_value_config",
+      "../logging:log_writer",
+      "../network:emulated_network",
+      "../scenario",
+      "../time_controller",
+    ]
+    absl_deps = [
+      "//third_party/abseil-cpp/absl/flags:flag",
+      "//third_party/abseil-cpp/absl/memory",
+    ]
+  }
+}
diff --git a/third_party/libwebrtc/test/peer_scenario/DEPS b/third_party/libwebrtc/test/peer_scenario/DEPS
new file mode 100644
index 0000000000..68e9f46087
--- /dev/null
+++ b/third_party/libwebrtc/test/peer_scenario/DEPS
@@ -0,0 +1,5 @@
+include_rules = [
+    "+pc",
+    "+p2p",
+]
+
diff --git a/third_party/libwebrtc/test/peer_scenario/peer_scenario.cc b/third_party/libwebrtc/test/peer_scenario/peer_scenario.cc
new file mode 100644
index 0000000000..485e33f67f
--- /dev/null
+++ b/third_party/libwebrtc/test/peer_scenario/peer_scenario.cc
@@ -0,0 +1,127 @@
+/*
+ *  Copyright (c) 2019 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 "test/peer_scenario/peer_scenario.h"
+
+#include "absl/flags/flag.h"
+#include "absl/memory/memory.h"
+#include "rtc_base/null_socket_server.h"
+#include "rtc_base/string_encode.h"
+#include "rtc_base/strings/string_builder.h"
+#include "test/logging/file_log_writer.h"
+#include "test/testsupport/file_utils.h"
+#include "test/time_controller/real_time_controller.h"
+#include "test/time_controller/simulated_time_controller.h"
+
+ABSL_FLAG(bool, peer_logs, false, "Save logs from peer scenario framework.");
+ABSL_FLAG(std::string,
+          peer_logs_root,
+          "",
+          "Output root path, based on project root if unset.");
+
+namespace webrtc {
+namespace test {
+namespace {
+std::unique_ptr<FileLogWriterFactory> GetPeerScenarioLogManager(
+    std::string file_name) {
+  if (absl::GetFlag(FLAGS_peer_logs) && !file_name.empty()) {
+    std::string output_root = absl::GetFlag(FLAGS_peer_logs_root);
+    if (output_root.empty())
+      output_root = OutputPath() + "output_data/";
+
+    auto base_filename = output_root + file_name + ".";
+    RTC_LOG(LS_INFO) << "Saving peer scenario logs to: " << base_filename;
+    return std::make_unique<FileLogWriterFactory>(base_filename);
+  }
+  return nullptr;
+}
+}  // namespace
+
+PeerScenario::PeerScenario(const testing::TestInfo& test_info, TimeMode mode)
+    : PeerScenario(
+          std::string(test_info.test_suite_name()) + "/" + test_info.name(),
+          mode) {}
+
+PeerScenario::PeerScenario(std::string file_name, TimeMode mode)
+    : PeerScenario(GetPeerScenarioLogManager(file_name), mode) {}
+
+PeerScenario::PeerScenario(
+    std::unique_ptr<LogWriterFactoryInterface> log_writer_manager,
+    TimeMode mode)
+    : log_writer_manager_(std::move(log_writer_manager)),
+      net_(mode, EmulatedNetworkStatsGatheringMode::kDefault),
+      signaling_thread_(net_.time_controller()->GetMainThread()) {}
+
+PeerScenarioClient* PeerScenario::CreateClient(
+    PeerScenarioClient::Config config) {
+  return CreateClient(
+      std::string("client_") + rtc::ToString(peer_clients_.size() + 1), config);
+}
+
+PeerScenarioClient* PeerScenario::CreateClient(
+    std::string name,
+    PeerScenarioClient::Config config) {
+  peer_clients_.emplace_back(net(), signaling_thread_,
+                             GetLogWriterFactory(name), config);
+  return &peer_clients_.back();
+}
+
+SignalingRoute PeerScenario::ConnectSignaling(
+    PeerScenarioClient* caller,
+    PeerScenarioClient* callee,
+    std::vector<EmulatedNetworkNode*> send_link,
+    std::vector<EmulatedNetworkNode*> ret_link) {
+  return SignalingRoute(caller, callee, net_.CreateCrossTrafficRoute(send_link),
+                        net_.CreateCrossTrafficRoute(ret_link));
+}
+
+void PeerScenario::SimpleConnection(
+    PeerScenarioClient* caller,
+    PeerScenarioClient* callee,
+    std::vector<EmulatedNetworkNode*> send_link,
+    std::vector<EmulatedNetworkNode*> ret_link) {
+  net()->CreateRoute(caller->endpoint(), send_link, callee->endpoint());
+  net()->CreateRoute(callee->endpoint(), ret_link, caller->endpoint());
+  auto signaling = ConnectSignaling(caller, callee, send_link, ret_link);
+  signaling.StartIceSignaling();
+  std::atomic<bool> done(false);
+  signaling.NegotiateSdp(
+      [&](const SessionDescriptionInterface&) { done = true; });
+  RTC_CHECK(WaitAndProcess(&done));
+}
+
+void PeerScenario::AttachVideoQualityAnalyzer(VideoQualityAnalyzer* analyzer,
+                                              VideoTrackInterface* send_track,
+                                              PeerScenarioClient* receiver) {
+  video_quality_pairs_.emplace_back(clock(), analyzer);
+  auto pair = &video_quality_pairs_.back();
+  send_track->AddOrUpdateSink(&pair->capture_tap_, rtc::VideoSinkWants());
+  receiver->AddVideoReceiveSink(send_track->id(), &pair->decode_tap_);
+}
+
+bool PeerScenario::WaitAndProcess(std::atomic<bool>* event,
+                                  TimeDelta max_duration) {
+  return net_.time_controller()->Wait([event] { return event->load(); },
+                                      max_duration);
+}
+
+void PeerScenario::ProcessMessages(TimeDelta duration) {
+  net_.time_controller()->AdvanceTime(duration);
+}
+
+std::unique_ptr<LogWriterFactoryInterface> PeerScenario::GetLogWriterFactory(
+    std::string name) {
+  if (!log_writer_manager_ || name.empty())
+    return nullptr;
+  return std::make_unique<LogWriterFactoryAddPrefix>(log_writer_manager_.get(),
+                                                     name);
+}
+
+}  // namespace test
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/test/peer_scenario/peer_scenario.h b/third_party/libwebrtc/test/peer_scenario/peer_scenario.h
new file mode 100644
index 0000000000..a177eeaac6
--- /dev/null
+++ b/third_party/libwebrtc/test/peer_scenario/peer_scenario.h
@@ -0,0 +1,122 @@
+/*
+ *  Copyright (c) 2019 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.
+ */
+#ifndef TEST_PEER_SCENARIO_PEER_SCENARIO_H_
+#define TEST_PEER_SCENARIO_PEER_SCENARIO_H_
+
+// The peer connection scenario test framework enables writing end to end unit
+// tests on the peer connection level. It's similar to the Scenario test but
+// uses the full stack, including SDP and ICE negotiation. This ensures that
+// features work end to end. It's also diffferent from the other tests on peer
+// connection level in that it does not rely on any mocks or fakes other than
+// for media input and networking. Additionally it provides direct access to the
+// underlying peer connection class.
+
+#include <list>
+#include <vector>
+
+#include "api/test/time_controller.h"
+#include "test/gtest.h"
+#include "test/logging/log_writer.h"
+#include "test/network/network_emulation_manager.h"
+#include "test/peer_scenario/peer_scenario_client.h"
+#include "test/peer_scenario/signaling_route.h"
+#include "test/scenario/stats_collection.h"
+#include "test/scenario/video_frame_matcher.h"
+
+namespace webrtc {
+namespace test {
+// The PeerScenario class represents a PeerConnection simulation scenario. The
+// main purpose is to maintain ownership and ensure safe destruction order of
+// clients and network emulation. Additionally it reduces the amount of boiler
+// plate requited for some actions. For example usage see the existing tests
+// using this class. Note that it should be used from a single calling thread.
+// This thread will also be assigned as the signaling thread for all peer
+// connections that are created. This means that the process methods must be
+// used when waiting to ensure that messages are processed on the signaling
+// thread.
+class PeerScenario {
+ public:
+  // The name is used for log output when those are enabled by the --peer_logs
+  // command line flag. Optionally, the TestInfo struct available in gtest can
+  // be used to automatically generate a path based on the test name.
+  explicit PeerScenario(const testing::TestInfo& test_info,
+                        TimeMode mode = TimeMode::kSimulated);
+  explicit PeerScenario(std::string file_name,
+                        TimeMode mode = TimeMode::kSimulated);
+  explicit PeerScenario(
+      std::unique_ptr<LogWriterFactoryInterface> log_writer_manager,
+      TimeMode mode = TimeMode::kSimulated);
+
+  NetworkEmulationManagerImpl* net() { return &net_; }
+
+  // Creates a client wrapping a peer connection conforming to the given config.
+  // The client  will share the signaling thread with the scenario. To maintain
+  // control of destruction order, ownership is kept within the scenario.
+  PeerScenarioClient* CreateClient(PeerScenarioClient::Config config);
+  PeerScenarioClient* CreateClient(std::string name,
+                                   PeerScenarioClient::Config config);
+
+  // Sets up a signaling route that can be used for SDP and ICE.
+  SignalingRoute ConnectSignaling(PeerScenarioClient* caller,
+                                  PeerScenarioClient* callee,
+                                  std::vector<EmulatedNetworkNode*> send_link,
+                                  std::vector<EmulatedNetworkNode*> ret_link);
+
+  // Connects two clients over given links. This will also start ICE signaling
+  // and SDP negotiation with default behavior. For customized behavior,
+  // ConnectSignaling should be used to allow more detailed control, for
+  // instance to allow different signaling and media routes.
+  void SimpleConnection(PeerScenarioClient* caller,
+                        PeerScenarioClient* callee,
+                        std::vector<EmulatedNetworkNode*> send_link,
+                        std::vector<EmulatedNetworkNode*> ret_link);
+
+  // Starts feeding the results of comparing captured frames from `send_track`
+  // with decoded frames on `receiver` to `analyzer`.
+  // TODO(srte): Provide a way to detach to allow removal of tracks.
+  void AttachVideoQualityAnalyzer(VideoQualityAnalyzer* analyzer,
+                                  VideoTrackInterface* send_track,
+                                  PeerScenarioClient* receiver);
+
+  // Waits on `event` while processing messages on the signaling thread.
+  bool WaitAndProcess(std::atomic<bool>* event,
+                      TimeDelta max_duration = TimeDelta::Seconds(5));
+
+  // Process messages on the signaling thread for the given duration.
+  void ProcessMessages(TimeDelta duration);
+
+ private:
+  // Helper struct to maintain ownership of the matcher and taps.
+  struct PeerVideoQualityPair {
+   public:
+    PeerVideoQualityPair(Clock* capture_clock, VideoQualityAnalyzer* analyzer)
+        : matcher_({analyzer->Handler()}),
+          capture_tap_(capture_clock, &matcher_),
+          decode_tap_(capture_clock, &matcher_, 0) {}
+    VideoFrameMatcher matcher_;
+    CapturedFrameTap capture_tap_;
+    DecodedFrameTap decode_tap_;
+  };
+
+  Clock* clock() { return Clock::GetRealTimeClock(); }
+
+  std::unique_ptr<LogWriterFactoryInterface> GetLogWriterFactory(
+      std::string name);
+
+  const std::unique_ptr<LogWriterFactoryInterface> log_writer_manager_;
+  NetworkEmulationManagerImpl net_;
+  rtc::Thread* const signaling_thread_;
+  std::list<PeerVideoQualityPair> video_quality_pairs_;
+  std::list<PeerScenarioClient> peer_clients_;
+};
+
+}  // namespace test
+}  // namespace webrtc
+#endif  // TEST_PEER_SCENARIO_PEER_SCENARIO_H_
diff --git a/third_party/libwebrtc/test/peer_scenario/peer_scenario_client.cc b/third_party/libwebrtc/test/peer_scenario/peer_scenario_client.cc
new file mode 100644
index 0000000000..5d77f17561
--- /dev/null
+++ b/third_party/libwebrtc/test/peer_scenario/peer_scenario_client.cc
@@ -0,0 +1,428 @@
+/*
+ *  Copyright (c) 2019 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 "test/peer_scenario/peer_scenario_client.h"
+
+#include <limits>
+#include <memory>
+#include <utility>
+
+#include "absl/memory/memory.h"
+#include "api/audio_codecs/builtin_audio_decoder_factory.h"
+#include "api/audio_codecs/builtin_audio_encoder_factory.h"
+#include "api/rtc_event_log/rtc_event_log_factory.h"
+#include "api/task_queue/default_task_queue_factory.h"
+#include "api/test/create_time_controller.h"
+#include "api/transport/field_trial_based_config.h"
+#include "api/video_codecs/builtin_video_decoder_factory.h"
+#include "api/video_codecs/builtin_video_encoder_factory.h"
+#include "media/engine/webrtc_media_engine.h"
+#include "modules/audio_device/include/test_audio_device.h"
+#include "p2p/client/basic_port_allocator.h"
+#include "test/fake_decoder.h"
+#include "test/fake_vp8_encoder.h"
+#include "test/frame_generator_capturer.h"
+
+namespace webrtc {
+namespace test {
+
+namespace {
+
+constexpr char kCommonStreamId[] = "stream_id";
+
+std::map<int, EmulatedEndpoint*> CreateEndpoints(
+    NetworkEmulationManager* net,
+    std::map<int, EmulatedEndpointConfig> endpoint_configs) {
+  std::map<int, EmulatedEndpoint*> endpoints;
+  for (const auto& kv : endpoint_configs)
+    endpoints[kv.first] = net->CreateEndpoint(kv.second);
+  return endpoints;
+}
+
+class LambdaPeerConnectionObserver final : public PeerConnectionObserver {
+ public:
+  explicit LambdaPeerConnectionObserver(
+      PeerScenarioClient::CallbackHandlers* handlers)
+      : handlers_(handlers) {}
+  void OnSignalingChange(
+      PeerConnectionInterface::SignalingState new_state) override {
+    for (const auto& handler : handlers_->on_signaling_change)
+      handler(new_state);
+  }
+  void OnDataChannel(
+      rtc::scoped_refptr<DataChannelInterface> data_channel) override {
+    for (const auto& handler : handlers_->on_data_channel)
+      handler(data_channel);
+  }
+  void OnRenegotiationNeeded() override {
+    for (const auto& handler : handlers_->on_renegotiation_needed)
+      handler();
+  }
+  void OnStandardizedIceConnectionChange(
+      PeerConnectionInterface::IceConnectionState new_state) override {
+    for (const auto& handler : handlers_->on_standardized_ice_connection_change)
+      handler(new_state);
+  }
+  void OnConnectionChange(
+      PeerConnectionInterface::PeerConnectionState new_state) override {
+    for (const auto& handler : handlers_->on_connection_change)
+      handler(new_state);
+  }
+  void OnIceGatheringChange(
+      PeerConnectionInterface::IceGatheringState new_state) override {
+    for (const auto& handler : handlers_->on_ice_gathering_change)
+      handler(new_state);
+  }
+  void OnIceCandidate(const IceCandidateInterface* candidate) override {
+    for (const auto& handler : handlers_->on_ice_candidate)
+      handler(candidate);
+  }
+  void OnIceCandidateError(const std::string& address,
+                           int port,
+                           const std::string& url,
+                           int error_code,
+                           const std::string& error_text) override {
+    for (const auto& handler : handlers_->on_ice_candidate_error)
+      handler(address, port, url, error_code, error_text);
+  }
+  void OnIceCandidatesRemoved(
+      const std::vector<cricket::Candidate>& candidates) override {
+    for (const auto& handler : handlers_->on_ice_candidates_removed)
+      handler(candidates);
+  }
+  void OnAddTrack(rtc::scoped_refptr<RtpReceiverInterface> receiver,
+                  const std::vector<rtc::scoped_refptr<MediaStreamInterface> >&
+                      streams) override {
+    for (const auto& handler : handlers_->on_add_track)
+      handler(receiver, streams);
+  }
+  void OnTrack(
+      rtc::scoped_refptr<RtpTransceiverInterface> transceiver) override {
+    for (const auto& handler : handlers_->on_track)
+      handler(transceiver);
+  }
+  void OnRemoveTrack(
+      rtc::scoped_refptr<RtpReceiverInterface> receiver) override {
+    for (const auto& handler : handlers_->on_remove_track)
+      handler(receiver);
+  }
+
+ private:
+  PeerScenarioClient::CallbackHandlers* handlers_;
+};
+
+class LambdaCreateSessionDescriptionObserver
+    : public CreateSessionDescriptionObserver {
+ public:
+  explicit LambdaCreateSessionDescriptionObserver(
+      std::function<void(std::unique_ptr<SessionDescriptionInterface> desc)>
+          on_success)
+      : on_success_(on_success) {}
+  void OnSuccess(SessionDescriptionInterface* desc) override {
+    // Takes ownership of answer, according to CreateSessionDescriptionObserver
+    // convention.
+    on_success_(absl::WrapUnique(desc));
+  }
+  void OnFailure(RTCError error) override {
+    RTC_DCHECK_NOTREACHED() << error.message();
+  }
+
+ private:
+  std::function<void(std::unique_ptr<SessionDescriptionInterface> desc)>
+      on_success_;
+};
+
+class LambdaSetLocalDescriptionObserver
+    : public SetLocalDescriptionObserverInterface {
+ public:
+  explicit LambdaSetLocalDescriptionObserver(
+      std::function<void(RTCError)> on_complete)
+      : on_complete_(on_complete) {}
+  void OnSetLocalDescriptionComplete(RTCError error) override {
+    on_complete_(error);
+  }
+
+ private:
+  std::function<void(RTCError)> on_complete_;
+};
+
+class LambdaSetRemoteDescriptionObserver
+    : public SetRemoteDescriptionObserverInterface {
+ public:
+  explicit LambdaSetRemoteDescriptionObserver(
+      std::function<void(RTCError)> on_complete)
+      : on_complete_(on_complete) {}
+  void OnSetRemoteDescriptionComplete(RTCError error) override {
+    on_complete_(error);
+  }
+
+ private:
+  std::function<void(RTCError)> on_complete_;
+};
+
+class FakeVideoEncoderFactory : public VideoEncoderFactory {
+ public:
+  FakeVideoEncoderFactory(Clock* clock) : clock_(clock) {}
+  std::vector<SdpVideoFormat> GetSupportedFormats() const override {
+    return {SdpVideoFormat("VP8")};
+  }
+  std::unique_ptr<VideoEncoder> CreateVideoEncoder(
+      const SdpVideoFormat& format) override {
+    RTC_CHECK_EQ(format.name, "VP8");
+    return std::make_unique<FakeVp8Encoder>(clock_);
+  }
+
+ private:
+  Clock* const clock_;
+};
+class FakeVideoDecoderFactory : public VideoDecoderFactory {
+ public:
+  std::vector<SdpVideoFormat> GetSupportedFormats() const override {
+    return {SdpVideoFormat("VP8")};
+  }
+  std::unique_ptr<VideoDecoder> CreateVideoDecoder(
+      const SdpVideoFormat& format) override {
+    return std::make_unique<FakeDecoder>();
+  }
+};
+}  // namespace
+
+PeerScenarioClient::PeerScenarioClient(
+    NetworkEmulationManager* net,
+    rtc::Thread* signaling_thread,
+    std::unique_ptr<LogWriterFactoryInterface> log_writer_factory,
+    PeerScenarioClient::Config config)
+    : endpoints_(CreateEndpoints(net, config.endpoints)),
+      task_queue_factory_(net->time_controller()->GetTaskQueueFactory()),
+      signaling_thread_(signaling_thread),
+      log_writer_factory_(std::move(log_writer_factory)),
+      worker_thread_(net->time_controller()->CreateThread("worker")),
+      handlers_(config.handlers),
+      observer_(new LambdaPeerConnectionObserver(&handlers_)) {
+  handlers_.on_track.push_back(
+      [this](rtc::scoped_refptr<RtpTransceiverInterface> transceiver) {
+        auto track = transceiver->receiver()->track().get();
+        if (track->kind() == MediaStreamTrackInterface::kVideoKind) {
+          auto* video = static_cast<VideoTrackInterface*>(track);
+          RTC_DCHECK_RUN_ON(signaling_thread_);
+          for (auto* sink : track_id_to_video_sinks_[track->id()]) {
+            video->AddOrUpdateSink(sink, rtc::VideoSinkWants());
+          }
+        }
+      });
+  handlers_.on_signaling_change.push_back(
+      [this](PeerConnectionInterface::SignalingState state) {
+        RTC_DCHECK_RUN_ON(signaling_thread_);
+        if (state == PeerConnectionInterface::SignalingState::kStable &&
+            peer_connection_->current_remote_description()) {
+          for (const auto& candidate : pending_ice_candidates_) {
+            RTC_CHECK(peer_connection_->AddIceCandidate(candidate.get()));
+          }
+          pending_ice_candidates_.clear();
+        }
+      });
+
+  std::vector<EmulatedEndpoint*> endpoints_vector;
+  for (const auto& kv : endpoints_)
+    endpoints_vector.push_back(kv.second);
+  auto* manager = net->CreateEmulatedNetworkManagerInterface(endpoints_vector);
+
+  PeerConnectionFactoryDependencies pcf_deps;
+  pcf_deps.network_thread = manager->network_thread();
+  pcf_deps.signaling_thread = signaling_thread_;
+  pcf_deps.worker_thread = worker_thread_.get();
+  pcf_deps.call_factory =
+      CreateTimeControllerBasedCallFactory(net->time_controller());
+  pcf_deps.task_queue_factory =
+      net->time_controller()->CreateTaskQueueFactory();
+  pcf_deps.event_log_factory =
+      std::make_unique<RtcEventLogFactory>(task_queue_factory_);
+  pcf_deps.trials = std::make_unique<FieldTrialBasedConfig>();
+
+  cricket::MediaEngineDependencies media_deps;
+  media_deps.task_queue_factory = task_queue_factory_;
+  media_deps.adm = TestAudioDeviceModule::Create(
+      task_queue_factory_,
+      TestAudioDeviceModule::CreatePulsedNoiseCapturer(
+          config.audio.pulsed_noise->amplitude *
+              std::numeric_limits<int16_t>::max(),
+          config.audio.sample_rate, config.audio.channels),
+      TestAudioDeviceModule::CreateDiscardRenderer(config.audio.sample_rate));
+
+  media_deps.audio_processing = AudioProcessingBuilder().Create();
+  if (config.video.use_fake_codecs) {
+    media_deps.video_encoder_factory =
+        std::make_unique<FakeVideoEncoderFactory>(
+            net->time_controller()->GetClock());
+    media_deps.video_decoder_factory =
+        std::make_unique<FakeVideoDecoderFactory>();
+  } else {
+    media_deps.video_encoder_factory = CreateBuiltinVideoEncoderFactory();
+    media_deps.video_decoder_factory = CreateBuiltinVideoDecoderFactory();
+  }
+  media_deps.audio_encoder_factory = CreateBuiltinAudioEncoderFactory();
+  media_deps.audio_decoder_factory = CreateBuiltinAudioDecoderFactory();
+  media_deps.trials = pcf_deps.trials.get();
+
+  pcf_deps.media_engine = cricket::CreateMediaEngine(std::move(media_deps));
+  pcf_deps.fec_controller_factory = nullptr;
+  pcf_deps.network_controller_factory = nullptr;
+  pcf_deps.network_state_predictor_factory = nullptr;
+
+  pc_factory_ = CreateModularPeerConnectionFactory(std::move(pcf_deps));
+  PeerConnectionFactoryInterface::Options pc_options;
+  pc_options.disable_encryption = config.disable_encryption;
+  pc_factory_->SetOptions(pc_options);
+
+  PeerConnectionDependencies pc_deps(observer_.get());
+  pc_deps.allocator = std::make_unique<cricket::BasicPortAllocator>(
+      manager->network_manager(), manager->packet_socket_factory());
+  pc_deps.allocator->set_flags(pc_deps.allocator->flags() |
+                               cricket::PORTALLOCATOR_DISABLE_TCP);
+  peer_connection_ =
+      pc_factory_
+          ->CreatePeerConnectionOrError(config.rtc_config, std::move(pc_deps))
+          .MoveValue();
+  if (log_writer_factory_) {
+    peer_connection_->StartRtcEventLog(log_writer_factory_->Create(".rtc.dat"),
+                                       /*output_period_ms=*/1000);
+  }
+}
+
+EmulatedEndpoint* PeerScenarioClient::endpoint(int index) {
+  RTC_CHECK_GT(endpoints_.size(), index);
+  return endpoints_.at(index);
+}
+
+PeerScenarioClient::AudioSendTrack PeerScenarioClient::CreateAudio(
+    std::string track_id,
+    cricket::AudioOptions options) {
+  RTC_DCHECK_RUN_ON(signaling_thread_);
+  AudioSendTrack res;
+  auto source = pc_factory_->CreateAudioSource(options);
+  auto track = pc_factory_->CreateAudioTrack(track_id, source.get());
+  res.track = track;
+  res.sender = peer_connection_->AddTrack(track, {kCommonStreamId}).value();
+  return res;
+}
+
+PeerScenarioClient::VideoSendTrack PeerScenarioClient::CreateVideo(
+    std::string track_id,
+    VideoSendTrackConfig config) {
+  RTC_DCHECK_RUN_ON(signaling_thread_);
+  VideoSendTrack res;
+  auto capturer = FrameGeneratorCapturer::Create(clock(), *task_queue_factory_,
+                                                 config.generator);
+  res.capturer = capturer.get();
+  capturer->Init();
+  res.source = rtc::make_ref_counted<FrameGeneratorCapturerVideoTrackSource>(
+      std::move(capturer), config.screencast);
+  auto track = pc_factory_->CreateVideoTrack(track_id, res.source.get());
+  res.track = track.get();
+  res.sender =
+      peer_connection_->AddTrack(track, {kCommonStreamId}).MoveValue().get();
+  return res;
+}
+
+void PeerScenarioClient::AddVideoReceiveSink(
+    std::string track_id,
+    rtc::VideoSinkInterface<VideoFrame>* video_sink) {
+  RTC_DCHECK_RUN_ON(signaling_thread_);
+  track_id_to_video_sinks_[track_id].push_back(video_sink);
+}
+
+void PeerScenarioClient::CreateAndSetSdp(
+    std::function<void(SessionDescriptionInterface*)> munge_offer,
+    std::function<void(std::string)> offer_handler) {
+  RTC_DCHECK_RUN_ON(signaling_thread_);
+  peer_connection_->CreateOffer(
+      rtc::make_ref_counted<LambdaCreateSessionDescriptionObserver>(
+          [=](std::unique_ptr<SessionDescriptionInterface> offer) {
+            RTC_DCHECK_RUN_ON(signaling_thread_);
+            if (munge_offer) {
+              munge_offer(offer.get());
+            }
+            std::string sdp_offer;
+            RTC_CHECK(offer->ToString(&sdp_offer));
+            peer_connection_->SetLocalDescription(
+                std::move(offer),
+                rtc::make_ref_counted<LambdaSetLocalDescriptionObserver>(
+                    [sdp_offer, offer_handler](RTCError) {
+                      offer_handler(sdp_offer);
+                    }));
+          })
+          .get(),
+      PeerConnectionInterface::RTCOfferAnswerOptions());
+}
+
+void PeerScenarioClient::SetSdpOfferAndGetAnswer(
+    std::string remote_offer,
+    std::function<void(std::string)> answer_handler) {
+  if (!signaling_thread_->IsCurrent()) {
+    signaling_thread_->PostTask(
+        [=] { SetSdpOfferAndGetAnswer(remote_offer, answer_handler); });
+    return;
+  }
+  RTC_DCHECK_RUN_ON(signaling_thread_);
+  peer_connection_->SetRemoteDescription(
+      CreateSessionDescription(SdpType::kOffer, remote_offer),
+      rtc::make_ref_counted<LambdaSetRemoteDescriptionObserver>([=](RTCError) {
+        RTC_DCHECK_RUN_ON(signaling_thread_);
+        peer_connection_->CreateAnswer(
+            rtc::make_ref_counted<LambdaCreateSessionDescriptionObserver>(
+                [=](std::unique_ptr<SessionDescriptionInterface> answer) {
+                  RTC_DCHECK_RUN_ON(signaling_thread_);
+                  std::string sdp_answer;
+                  answer->ToString(&sdp_answer);
+                  RTC_LOG(LS_INFO) << sdp_answer;
+                  peer_connection_->SetLocalDescription(
+                      std::move(answer),
+                      rtc::make_ref_counted<LambdaSetLocalDescriptionObserver>(
+                          [answer_handler, sdp_answer](RTCError) {
+                            answer_handler(sdp_answer);
+                          }));
+                })
+                .get(),
+            PeerConnectionInterface::RTCOfferAnswerOptions());
+      }));
+}
+
+void PeerScenarioClient::SetSdpAnswer(
+    std::string remote_answer,
+    std::function<void(const SessionDescriptionInterface&)> done_handler) {
+  if (!signaling_thread_->IsCurrent()) {
+    signaling_thread_->PostTask(
+        [=] { SetSdpAnswer(remote_answer, done_handler); });
+    return;
+  }
+  RTC_DCHECK_RUN_ON(signaling_thread_);
+  peer_connection_->SetRemoteDescription(
+      CreateSessionDescription(SdpType::kAnswer, remote_answer),
+      rtc::make_ref_counted<LambdaSetRemoteDescriptionObserver>(
+          [remote_answer, done_handler](RTCError) {
+            auto answer =
+                CreateSessionDescription(SdpType::kAnswer, remote_answer);
+            done_handler(*answer);
+          }));
+}
+
+void PeerScenarioClient::AddIceCandidate(
+    std::unique_ptr<IceCandidateInterface> candidate) {
+  RTC_DCHECK_RUN_ON(signaling_thread_);
+  if (peer_connection_->signaling_state() ==
+          PeerConnectionInterface::SignalingState::kStable &&
+      peer_connection_->current_remote_description()) {
+    RTC_CHECK(peer_connection_->AddIceCandidate(candidate.get()));
+  } else {
+    pending_ice_candidates_.push_back(std::move(candidate));
+  }
+}
+
+}  // namespace test
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/test/peer_scenario/peer_scenario_client.h b/third_party/libwebrtc/test/peer_scenario/peer_scenario_client.h
new file mode 100644
index 0000000000..ab6aac9cf8
--- /dev/null
+++ b/third_party/libwebrtc/test/peer_scenario/peer_scenario_client.h
@@ -0,0 +1,179 @@
+/*
+ *  Copyright (c) 2019 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.
+ */
+#ifndef TEST_PEER_SCENARIO_PEER_SCENARIO_CLIENT_H_
+#define TEST_PEER_SCENARIO_PEER_SCENARIO_CLIENT_H_
+
+#include <functional>
+#include <list>
+#include <map>
+#include <memory>
+#include <string>
+#include <vector>
+
+#include "absl/memory/memory.h"
+#include "api/peer_connection_interface.h"
+#include "api/test/network_emulation_manager.h"
+#include "api/test/time_controller.h"
+#include "pc/test/frame_generator_capturer_video_track_source.h"
+#include "test/logging/log_writer.h"
+
+namespace webrtc {
+namespace test {
+
+// Wrapper for a PeerConnection for use in PeerScenario tests. It's intended to
+// be a minimal wrapper for a peer connection that's simple to use in testing.
+// In particular the constructor hides a lot of the required setup for a peer
+// connection.
+class PeerScenarioClient {
+ public:
+  struct CallbackHandlers {
+    std::vector<std::function<void(PeerConnectionInterface::SignalingState)>>
+        on_signaling_change;
+    std::vector<std::function<void(rtc::scoped_refptr<DataChannelInterface>)>>
+        on_data_channel;
+    std::vector<std::function<void()>> on_renegotiation_needed;
+    std::vector<
+        std::function<void(PeerConnectionInterface::IceConnectionState)>>
+        on_standardized_ice_connection_change;
+    std::vector<
+        std::function<void(PeerConnectionInterface::PeerConnectionState)>>
+        on_connection_change;
+    std::vector<std::function<void(PeerConnectionInterface::IceGatheringState)>>
+        on_ice_gathering_change;
+    std::vector<std::function<void(const IceCandidateInterface*)>>
+        on_ice_candidate;
+    std::vector<std::function<void(const std::string&,
+                                   int,
+                                   const std::string&,
+                                   int,
+                                   const std::string&)>>
+        on_ice_candidate_error;
+    std::vector<std::function<void(const std::vector<cricket::Candidate>&)>>
+        on_ice_candidates_removed;
+    std::vector<std::function<void(
+        rtc::scoped_refptr<RtpReceiverInterface>,
+        const std::vector<rtc::scoped_refptr<MediaStreamInterface>>&)>>
+        on_add_track;
+    std::vector<
+        std::function<void(rtc::scoped_refptr<RtpTransceiverInterface>)>>
+        on_track;
+    std::vector<std::function<void(rtc::scoped_refptr<RtpReceiverInterface>)>>
+        on_remove_track;
+  };
+  struct Config {
+    // WebRTC only support one audio device that is setup up on construction, so
+    // we provide the audio generator configuration here rather than on creation
+    // of the tracks. This is unlike video, where multiple capture sources can
+    // be used at the same time.
+    struct AudioSource {
+      int sample_rate = 48000;
+      int channels = 1;
+      struct PulsedNoise {
+        double amplitude = 0.1;
+      };
+      absl::optional<PulsedNoise> pulsed_noise = PulsedNoise();
+    } audio;
+    struct Video {
+      bool use_fake_codecs = false;
+    } video;
+    // The created endpoints can be accessed using the map key as `index` in
+    // PeerScenarioClient::endpoint(index).
+    std::map<int, EmulatedEndpointConfig> endpoints = {
+        {0, EmulatedEndpointConfig()}};
+    CallbackHandlers handlers;
+    PeerConnectionInterface::RTCConfiguration rtc_config;
+    bool disable_encryption = false;
+    Config() { rtc_config.sdp_semantics = SdpSemantics::kUnifiedPlan; }
+  };
+
+  struct VideoSendTrackConfig {
+    FrameGeneratorCapturerConfig generator;
+    bool screencast = false;
+  };
+
+  struct AudioSendTrack {
+    rtc::scoped_refptr<AudioTrackInterface> track;
+    rtc::scoped_refptr<RtpSenderInterface> sender;
+  };
+
+  struct VideoSendTrack {
+    // Raw pointer to the capturer owned by `source`.
+    FrameGeneratorCapturer* capturer;
+    rtc::scoped_refptr<FrameGeneratorCapturerVideoTrackSource> source;
+    rtc::scoped_refptr<VideoTrackInterface> track;
+    rtc::scoped_refptr<RtpSenderInterface> sender;
+  };
+
+  PeerScenarioClient(
+      NetworkEmulationManager* net,
+      rtc::Thread* signaling_thread,
+      std::unique_ptr<LogWriterFactoryInterface> log_writer_factory,
+      Config config);
+
+  PeerConnectionFactoryInterface* factory() { return pc_factory_.get(); }
+  PeerConnectionInterface* pc() {
+    RTC_DCHECK_RUN_ON(signaling_thread_);
+    return peer_connection_.get();
+  }
+  rtc::Thread* thread() { return signaling_thread_; }
+  Clock* clock() { return Clock::GetRealTimeClock(); }
+
+  // Returns the endpoint created from the EmulatedEndpointConfig with the same
+  // index in PeerScenarioClient::config.
+  EmulatedEndpoint* endpoint(int index = 0);
+
+  AudioSendTrack CreateAudio(std::string track_id,
+                             cricket::AudioOptions options);
+  VideoSendTrack CreateVideo(std::string track_id, VideoSendTrackConfig config);
+
+  void AddVideoReceiveSink(std::string track_id,
+                           rtc::VideoSinkInterface<VideoFrame>* video_sink);
+
+  CallbackHandlers* handlers() { return &handlers_; }
+
+  // The `munge_offer` function can be used to munge the SDP, i.e. modify a
+  // local description afer creating it but before setting it. Note that this is
+  // legacy behavior. It's added here only to be able to have test coverage for
+  // scenarios even if they are not spec compliant.
+  void CreateAndSetSdp(
+      std::function<void(SessionDescriptionInterface*)> munge_offer,
+      std::function<void(std::string)> offer_handler);
+  void SetSdpOfferAndGetAnswer(std::string remote_offer,
+                               std::function<void(std::string)> answer_handler);
+  void SetSdpAnswer(
+      std::string remote_answer,
+      std::function<void(const SessionDescriptionInterface& answer)>
+          done_handler);
+
+  // Adds the given ice candidate when the peer connection is ready.
+  void AddIceCandidate(std::unique_ptr<IceCandidateInterface> candidate);
+
+ private:
+  const std::map<int, EmulatedEndpoint*> endpoints_;
+  TaskQueueFactory* const task_queue_factory_;
+  rtc::Thread* const signaling_thread_;
+  const std::unique_ptr<LogWriterFactoryInterface> log_writer_factory_;
+  const std::unique_ptr<rtc::Thread> worker_thread_;
+  CallbackHandlers handlers_ RTC_GUARDED_BY(signaling_thread_);
+  const std::unique_ptr<PeerConnectionObserver> observer_;
+  std::map<std::string, std::vector<rtc::VideoSinkInterface<VideoFrame>*>>
+      track_id_to_video_sinks_ RTC_GUARDED_BY(signaling_thread_);
+  std::list<std::unique_ptr<IceCandidateInterface>> pending_ice_candidates_
+      RTC_GUARDED_BY(signaling_thread_);
+
+  rtc::scoped_refptr<PeerConnectionFactoryInterface> pc_factory_;
+  rtc::scoped_refptr<PeerConnectionInterface> peer_connection_
+      RTC_GUARDED_BY(signaling_thread_);
+};
+
+}  // namespace test
+}  // namespace webrtc
+
+#endif  // TEST_PEER_SCENARIO_PEER_SCENARIO_CLIENT_H_
diff --git a/third_party/libwebrtc/test/peer_scenario/scenario_connection.cc b/third_party/libwebrtc/test/peer_scenario/scenario_connection.cc
new file mode 100644
index 0000000000..66eca275d1
--- /dev/null
+++ b/third_party/libwebrtc/test/peer_scenario/scenario_connection.cc
@@ -0,0 +1,242 @@
+/*
+ *  Copyright (c) 2019 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 "test/peer_scenario/scenario_connection.h"
+
+#include "absl/memory/memory.h"
+#include "media/base/rtp_utils.h"
+#include "modules/rtp_rtcp/source/rtp_packet_received.h"
+#include "p2p/client/basic_port_allocator.h"
+#include "pc/channel.h"
+#include "pc/jsep_transport_controller.h"
+#include "pc/rtp_transport_internal.h"
+#include "pc/session_description.h"
+#include "rtc_base/task_queue_for_test.h"
+
+namespace webrtc {
+class ScenarioIceConnectionImpl : public ScenarioIceConnection,
+                                  public sigslot::has_slots<>,
+                                  private JsepTransportController::Observer,
+                                  private RtpPacketSinkInterface {
+ public:
+  ScenarioIceConnectionImpl(test::NetworkEmulationManagerImpl* net,
+                            IceConnectionObserver* observer);
+  ~ScenarioIceConnectionImpl() override;
+
+  void SendRtpPacket(rtc::ArrayView<const uint8_t> packet_view) override;
+  void SendRtcpPacket(rtc::ArrayView<const uint8_t> packet_view) override;
+
+  void SetRemoteSdp(SdpType type, const std::string& remote_sdp) override;
+  void SetLocalSdp(SdpType type, const std::string& local_sdp) override;
+
+  EmulatedEndpoint* endpoint() override { return endpoint_; }
+  const cricket::TransportDescription& transport_description() const override {
+    return transport_description_;
+  }
+
+ private:
+  JsepTransportController::Config CreateJsepConfig();
+  bool OnTransportChanged(
+      const std::string& mid,
+      RtpTransportInternal* rtp_transport,
+      rtc::scoped_refptr<DtlsTransport> dtls_transport,
+      DataChannelTransportInterface* data_channel_transport) override;
+
+  void OnRtpPacket(const RtpPacketReceived& packet) override;
+  void OnCandidates(const std::string& mid,
+                    const std::vector<cricket::Candidate>& candidates);
+
+  IceConnectionObserver* const observer_;
+  EmulatedEndpoint* const endpoint_;
+  EmulatedNetworkManagerInterface* const manager_;
+  rtc::Thread* const signaling_thread_;
+  rtc::Thread* const network_thread_;
+  rtc::scoped_refptr<rtc::RTCCertificate> const certificate_
+      RTC_GUARDED_BY(network_thread_);
+  cricket::TransportDescription const transport_description_
+      RTC_GUARDED_BY(signaling_thread_);
+  std::unique_ptr<cricket::BasicPortAllocator> port_allocator_
+      RTC_GUARDED_BY(network_thread_);
+  std::unique_ptr<JsepTransportController> jsep_controller_;
+  RtpTransportInternal* rtp_transport_ RTC_GUARDED_BY(network_thread_) =
+      nullptr;
+  std::unique_ptr<SessionDescriptionInterface> remote_description_
+      RTC_GUARDED_BY(signaling_thread_);
+  std::unique_ptr<SessionDescriptionInterface> local_description_
+      RTC_GUARDED_BY(signaling_thread_);
+};
+
+std::unique_ptr<ScenarioIceConnection> ScenarioIceConnection::Create(
+    webrtc::test::NetworkEmulationManagerImpl* net,
+    IceConnectionObserver* observer) {
+  return std::make_unique<ScenarioIceConnectionImpl>(net, observer);
+}
+
+ScenarioIceConnectionImpl::ScenarioIceConnectionImpl(
+    test::NetworkEmulationManagerImpl* net,
+    IceConnectionObserver* observer)
+    : observer_(observer),
+      endpoint_(net->CreateEndpoint(EmulatedEndpointConfig())),
+      manager_(net->CreateEmulatedNetworkManagerInterface({endpoint_})),
+      signaling_thread_(rtc::Thread::Current()),
+      network_thread_(manager_->network_thread()),
+      certificate_(rtc::RTCCertificate::Create(
+          rtc::SSLIdentity::Create("", ::rtc::KT_DEFAULT))),
+      transport_description_(
+          /*transport_options*/ {},
+          rtc::CreateRandomString(cricket::ICE_UFRAG_LENGTH),
+          rtc::CreateRandomString(cricket::ICE_PWD_LENGTH),
+          cricket::IceMode::ICEMODE_FULL,
+          cricket::ConnectionRole::CONNECTIONROLE_PASSIVE,
+          rtc::SSLFingerprint::CreateFromCertificate(*certificate_.get())
+              .get()),
+      port_allocator_(
+          new cricket::BasicPortAllocator(manager_->network_manager(),
+                                          manager_->packet_socket_factory())),
+      jsep_controller_(
+          new JsepTransportController(network_thread_,
+                                      port_allocator_.get(),
+                                      /*async_resolver_factory*/ nullptr,
+                                      CreateJsepConfig())) {
+  SendTask(network_thread_, [this] {
+    RTC_DCHECK_RUN_ON(network_thread_);
+    uint32_t flags = cricket::PORTALLOCATOR_DISABLE_TCP;
+    port_allocator_->set_flags(port_allocator_->flags() | flags);
+    port_allocator_->Initialize();
+    RTC_CHECK(port_allocator_->SetConfiguration(/*stun_servers*/ {},
+                                                /*turn_servers*/ {}, 0,
+                                                webrtc::NO_PRUNE));
+    jsep_controller_->SetLocalCertificate(certificate_);
+  });
+}
+
+ScenarioIceConnectionImpl::~ScenarioIceConnectionImpl() {
+  SendTask(network_thread_, [this] {
+    RTC_DCHECK_RUN_ON(network_thread_);
+    jsep_controller_.reset();
+    port_allocator_.reset();
+    rtp_transport_ = nullptr;
+  });
+}
+
+JsepTransportController::Config ScenarioIceConnectionImpl::CreateJsepConfig() {
+  JsepTransportController::Config config;
+  config.transport_observer = this;
+  config.bundle_policy =
+      PeerConnectionInterface::BundlePolicy::kBundlePolicyMaxBundle;
+  config.rtcp_handler = [this](const rtc::CopyOnWriteBuffer& packet,
+                               int64_t packet_time_us) {
+    RTC_DCHECK_RUN_ON(network_thread_);
+    observer_->OnPacketReceived(packet);
+  };
+  config.field_trials = &field_trials;
+  return config;
+}
+
+void ScenarioIceConnectionImpl::SendRtpPacket(
+    rtc::ArrayView<const uint8_t> packet_view) {
+  rtc::CopyOnWriteBuffer packet(packet_view.data(), packet_view.size(),
+                                ::cricket::kMaxRtpPacketLen);
+  network_thread_->PostTask([this, packet = std::move(packet)]() mutable {
+    RTC_DCHECK_RUN_ON(network_thread_);
+    if (rtp_transport_ != nullptr)
+      rtp_transport_->SendRtpPacket(&packet, rtc::PacketOptions(),
+                                    cricket::PF_SRTP_BYPASS);
+  });
+}
+
+void ScenarioIceConnectionImpl::SendRtcpPacket(
+    rtc::ArrayView<const uint8_t> packet_view) {
+  rtc::CopyOnWriteBuffer packet(packet_view.data(), packet_view.size(),
+                                ::cricket::kMaxRtpPacketLen);
+  network_thread_->PostTask([this, packet = std::move(packet)]() mutable {
+    RTC_DCHECK_RUN_ON(network_thread_);
+    if (rtp_transport_ != nullptr)
+      rtp_transport_->SendRtcpPacket(&packet, rtc::PacketOptions(),
+                                     cricket::PF_SRTP_BYPASS);
+  });
+}
+void ScenarioIceConnectionImpl::SetRemoteSdp(SdpType type,
+                                             const std::string& remote_sdp) {
+  RTC_DCHECK_RUN_ON(signaling_thread_);
+  remote_description_ = webrtc::CreateSessionDescription(type, remote_sdp);
+  jsep_controller_->SubscribeIceCandidateGathered(
+      [this](const std::string& transport,
+             const std::vector<cricket::Candidate>& candidate) {
+        ScenarioIceConnectionImpl::OnCandidates(transport, candidate);
+      });
+
+  auto res = jsep_controller_->SetRemoteDescription(
+      remote_description_->GetType(), remote_description_->description());
+  RTC_CHECK(res.ok()) << res.message();
+  RtpDemuxerCriteria criteria;
+  for (const auto& content : remote_description_->description()->contents()) {
+    if (content.media_description()->as_audio()) {
+      for (const auto& codec :
+           content.media_description()->as_audio()->codecs()) {
+        criteria.payload_types().insert(codec.id);
+      }
+    }
+    if (content.media_description()->as_video()) {
+      for (const auto& codec :
+           content.media_description()->as_video()->codecs()) {
+        criteria.payload_types().insert(codec.id);
+      }
+    }
+  }
+
+  network_thread_->PostTask([this, criteria]() {
+    RTC_DCHECK_RUN_ON(network_thread_);
+    RTC_DCHECK(rtp_transport_);
+    rtp_transport_->RegisterRtpDemuxerSink(criteria, this);
+  });
+}
+
+void ScenarioIceConnectionImpl::SetLocalSdp(SdpType type,
+                                            const std::string& local_sdp) {
+  RTC_DCHECK_RUN_ON(signaling_thread_);
+  local_description_ = webrtc::CreateSessionDescription(type, local_sdp);
+  auto res = jsep_controller_->SetLocalDescription(
+      local_description_->GetType(), local_description_->description());
+  RTC_CHECK(res.ok()) << res.message();
+  jsep_controller_->MaybeStartGathering();
+}
+
+bool ScenarioIceConnectionImpl::OnTransportChanged(
+    const std::string& mid,
+    RtpTransportInternal* rtp_transport,
+    rtc::scoped_refptr<DtlsTransport> dtls_transport,
+    DataChannelTransportInterface* data_channel_transport) {
+  RTC_DCHECK_RUN_ON(network_thread_);
+  if (rtp_transport == nullptr) {
+    rtp_transport_->UnregisterRtpDemuxerSink(this);
+  } else {
+    RTC_DCHECK(rtp_transport_ == nullptr || rtp_transport_ == rtp_transport);
+    if (rtp_transport_ != rtp_transport) {
+      rtp_transport_ = rtp_transport;
+    }
+    RtpDemuxerCriteria criteria(mid);
+    rtp_transport_->RegisterRtpDemuxerSink(criteria, this);
+  }
+  return true;
+}
+
+void ScenarioIceConnectionImpl::OnRtpPacket(const RtpPacketReceived& packet) {
+  RTC_DCHECK_RUN_ON(network_thread_);
+  observer_->OnPacketReceived(packet.Buffer());
+}
+
+void ScenarioIceConnectionImpl::OnCandidates(
+    const std::string& mid,
+    const std::vector<cricket::Candidate>& candidates) {
+  RTC_DCHECK_RUN_ON(signaling_thread_);
+  observer_->OnIceCandidates(mid, candidates);
+}
+
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/test/peer_scenario/scenario_connection.h b/third_party/libwebrtc/test/peer_scenario/scenario_connection.h
new file mode 100644
index 0000000000..e8cef527c5
--- /dev/null
+++ b/third_party/libwebrtc/test/peer_scenario/scenario_connection.h
@@ -0,0 +1,66 @@
+/*
+ *  Copyright (c) 2019 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.
+ */
+#ifndef TEST_PEER_SCENARIO_SCENARIO_CONNECTION_H_
+#define TEST_PEER_SCENARIO_SCENARIO_CONNECTION_H_
+
+#include <functional>
+#include <memory>
+#include <string>
+#include <vector>
+
+#include "api/candidate.h"
+#include "api/jsep.h"
+#include "p2p/base/transport_description.h"
+#include "test/network/network_emulation_manager.h"
+#include "test/scoped_key_value_config.h"
+
+namespace webrtc {
+
+// ScenarioIceConnection provides the transport level functionality of a
+// PeerConnection for use in peer connection scenario tests. This allows
+// implementing custom server side behavior in tests.
+class ScenarioIceConnection {
+ public:
+  class IceConnectionObserver {
+   public:
+    // Called on network thread.
+    virtual void OnPacketReceived(rtc::CopyOnWriteBuffer packet) = 0;
+    // Called on signaling thread.
+    virtual void OnIceCandidates(
+        const std::string& mid,
+        const std::vector<cricket::Candidate>& candidates) = 0;
+
+   protected:
+    ~IceConnectionObserver() = default;
+  };
+  static std::unique_ptr<ScenarioIceConnection> Create(
+      test::NetworkEmulationManagerImpl* net,
+      IceConnectionObserver* observer);
+
+  virtual ~ScenarioIceConnection() = default;
+
+  // Posts tasks to send packets to network thread.
+  virtual void SendRtpPacket(rtc::ArrayView<const uint8_t> packet_view) = 0;
+  virtual void SendRtcpPacket(rtc::ArrayView<const uint8_t> packet_view) = 0;
+
+  // Used for ICE configuration, called on signaling thread.
+  virtual void SetRemoteSdp(SdpType type, const std::string& remote_sdp) = 0;
+  virtual void SetLocalSdp(SdpType type, const std::string& local_sdp) = 0;
+
+  virtual EmulatedEndpoint* endpoint() = 0;
+  virtual const cricket::TransportDescription& transport_description()
+      const = 0;
+
+  webrtc::test::ScopedKeyValueConfig field_trials;
+};
+
+}  // namespace webrtc
+
+#endif  // TEST_PEER_SCENARIO_SCENARIO_CONNECTION_H_
diff --git a/third_party/libwebrtc/test/peer_scenario/signaling_route.cc b/third_party/libwebrtc/test/peer_scenario/signaling_route.cc
new file mode 100644
index 0000000000..eeec7c8657
--- /dev/null
+++ b/third_party/libwebrtc/test/peer_scenario/signaling_route.cc
@@ -0,0 +1,114 @@
+/*
+ *  Copyright (c) 2019 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 "test/peer_scenario/signaling_route.h"
+
+#include <memory>
+
+#include "test/network/network_emulation_manager.h"
+
+namespace webrtc {
+namespace test {
+namespace {
+constexpr size_t kIcePacketSize = 400;
+constexpr size_t kSdpPacketSize = 1200;
+
+struct IceMessage {
+  IceMessage() = default;
+  explicit IceMessage(const IceCandidateInterface* candidate)
+      : sdp_mid(candidate->sdp_mid()),
+        sdp_mline_index(candidate->sdp_mline_index()) {
+    RTC_CHECK(candidate->ToString(&sdp_line));
+  }
+  std::unique_ptr<IceCandidateInterface> AsCandidate() const {
+    SdpParseError err;
+    std::unique_ptr<IceCandidateInterface> candidate(
+        CreateIceCandidate(sdp_mid, sdp_mline_index, sdp_line, &err));
+    RTC_CHECK(candidate) << "Failed to parse: \"" << err.line
+                         << "\". Reason: " << err.description;
+    return candidate;
+  }
+  std::string sdp_mid;
+  int sdp_mline_index;
+  std::string sdp_line;
+};
+
+void StartIceSignalingForRoute(PeerScenarioClient* caller,
+                               PeerScenarioClient* callee,
+                               CrossTrafficRoute* send_route) {
+  caller->handlers()->on_ice_candidate.push_back(
+      [=](const IceCandidateInterface* candidate) {
+        IceMessage msg(candidate);
+        send_route->NetworkDelayedAction(kIcePacketSize, [callee, msg]() {
+          callee->thread()->PostTask(
+              [callee, msg]() { callee->AddIceCandidate(msg.AsCandidate()); });
+        });
+      });
+}
+
+void StartSdpNegotiation(
+    PeerScenarioClient* caller,
+    PeerScenarioClient* callee,
+    CrossTrafficRoute* send_route,
+    CrossTrafficRoute* ret_route,
+    std::function<void(SessionDescriptionInterface* offer)> munge_offer,
+    std::function<void(SessionDescriptionInterface*)> modify_offer,
+    std::function<void(const SessionDescriptionInterface&)> exchange_finished) {
+  caller->CreateAndSetSdp(munge_offer, [=](std::string sdp_offer) {
+    if (modify_offer) {
+      auto offer = CreateSessionDescription(SdpType::kOffer, sdp_offer);
+      modify_offer(offer.get());
+      RTC_CHECK(offer->ToString(&sdp_offer));
+    }
+    send_route->NetworkDelayedAction(kSdpPacketSize, [=] {
+      callee->SetSdpOfferAndGetAnswer(sdp_offer, [=](std::string answer) {
+        ret_route->NetworkDelayedAction(kSdpPacketSize, [=] {
+          caller->SetSdpAnswer(std::move(answer), std::move(exchange_finished));
+        });
+      });
+    });
+  });
+}
+}  // namespace
+
+SignalingRoute::SignalingRoute(PeerScenarioClient* caller,
+                               PeerScenarioClient* callee,
+                               CrossTrafficRoute* send_route,
+                               CrossTrafficRoute* ret_route)
+    : caller_(caller),
+      callee_(callee),
+      send_route_(send_route),
+      ret_route_(ret_route) {}
+
+void SignalingRoute::StartIceSignaling() {
+  StartIceSignalingForRoute(caller_, callee_, send_route_);
+  StartIceSignalingForRoute(callee_, caller_, ret_route_);
+}
+
+void SignalingRoute::NegotiateSdp(
+    std::function<void(SessionDescriptionInterface*)> munge_offer,
+    std::function<void(SessionDescriptionInterface*)> modify_offer,
+    std::function<void(const SessionDescriptionInterface&)> exchange_finished) {
+  StartSdpNegotiation(caller_, callee_, send_route_, ret_route_, munge_offer,
+                      modify_offer, exchange_finished);
+}
+
+void SignalingRoute::NegotiateSdp(
+    std::function<void(SessionDescriptionInterface*)> modify_offer,
+    std::function<void(const SessionDescriptionInterface&)> exchange_finished) {
+  NegotiateSdp({}, modify_offer, exchange_finished);
+}
+
+void SignalingRoute::NegotiateSdp(
+    std::function<void(const SessionDescriptionInterface&)> exchange_finished) {
+  NegotiateSdp({}, {}, exchange_finished);
+}
+
+}  // namespace test
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/test/peer_scenario/signaling_route.h b/third_party/libwebrtc/test/peer_scenario/signaling_route.h
new file mode 100644
index 0000000000..a95ae5c9f7
--- /dev/null
+++ b/third_party/libwebrtc/test/peer_scenario/signaling_route.h
@@ -0,0 +1,67 @@
+/*
+ *  Copyright (c) 2019 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.
+ */
+#ifndef TEST_PEER_SCENARIO_SIGNALING_ROUTE_H_
+#define TEST_PEER_SCENARIO_SIGNALING_ROUTE_H_
+
+#include <string>
+#include <utility>
+
+#include "test/network/network_emulation_manager.h"
+#include "test/peer_scenario/peer_scenario_client.h"
+
+namespace webrtc {
+namespace test {
+
+// Helper class to reduce the amount of boilerplate required for ICE signalling
+// ad SDP negotiation.
+class SignalingRoute {
+ public:
+  SignalingRoute(PeerScenarioClient* caller,
+                 PeerScenarioClient* callee,
+                 CrossTrafficRoute* send_route,
+                 CrossTrafficRoute* ret_route);
+
+  void StartIceSignaling();
+
+  // The `modify_offer` callback is used to modify an offer after the local
+  // description has been set. This is legal (but odd) behavior.
+  // The `munge_offer` callback is used to modify an offer between its creation
+  // and set local description. This behavior is forbidden according to the spec
+  // but available here in order to allow test coverage on corner cases.
+  // The `exchange_finished` callback is called with the answer produced after
+  // SDP negotations has completed.
+  // TODO(srte): Handle lossy links.
+  void NegotiateSdp(
+      std::function<void(SessionDescriptionInterface* offer)> munge_offer,
+      std::function<void(SessionDescriptionInterface* offer)> modify_offer,
+      std::function<void(const SessionDescriptionInterface& answer)>
+          exchange_finished);
+  void NegotiateSdp(
+      std::function<void(SessionDescriptionInterface* offer)> modify_offer,
+      std::function<void(const SessionDescriptionInterface& answer)>
+          exchange_finished);
+  void NegotiateSdp(
+      std::function<void(const SessionDescriptionInterface& answer)>
+          exchange_finished);
+  SignalingRoute reverse() {
+    return SignalingRoute(callee_, caller_, ret_route_, send_route_);
+  }
+
+ private:
+  PeerScenarioClient* const caller_;
+  PeerScenarioClient* const callee_;
+  CrossTrafficRoute* const send_route_;
+  CrossTrafficRoute* const ret_route_;
+};
+
+}  // namespace test
+}  // namespace webrtc
+
+#endif  // TEST_PEER_SCENARIO_SIGNALING_ROUTE_H_
diff --git a/third_party/libwebrtc/test/peer_scenario/tests/BUILD.gn b/third_party/libwebrtc/test/peer_scenario/tests/BUILD.gn
new file mode 100644
index 0000000000..ba6ec20e84
--- /dev/null
+++ b/third_party/libwebrtc/test/peer_scenario/tests/BUILD.gn
@@ -0,0 +1,30 @@
+# Copyright (c) 2019 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.
+
+import("../../../webrtc.gni")
+
+if (rtc_include_tests) {
+  rtc_library("tests") {
+    testonly = true
+    sources = [
+      "peer_scenario_quality_test.cc",
+      "remote_estimate_test.cc",
+      "unsignaled_stream_test.cc",
+    ]
+    deps = [
+      "..:peer_scenario",
+      "../../:field_trial",
+      "../../:test_support",
+      "../../../media:rtc_media_base",
+      "../../../media:stream_params",
+      "../../../modules/rtp_rtcp:rtp_rtcp_format",
+      "../../../pc:media_session",
+      "../../../pc:session_description",
+    ]
+  }
+}
diff --git a/third_party/libwebrtc/test/peer_scenario/tests/peer_scenario_quality_test.cc b/third_party/libwebrtc/test/peer_scenario/tests/peer_scenario_quality_test.cc
new file mode 100644
index 0000000000..911a68720f
--- /dev/null
+++ b/third_party/libwebrtc/test/peer_scenario/tests/peer_scenario_quality_test.cc
@@ -0,0 +1,46 @@
+/*
+ *  Copyright (c) 2019 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 "test/gtest.h"
+#include "test/peer_scenario/peer_scenario.h"
+#include "test/peer_scenario/peer_scenario_client.h"
+
+namespace webrtc {
+namespace test {
+#if defined(WEBRTC_WIN)
+#define MAYBE_PsnrIsCollected DISABLED_PsnrIsCollected
+#else
+#define MAYBE_PsnrIsCollected PsnrIsCollected
+#endif
+TEST(PeerScenarioQualityTest, MAYBE_PsnrIsCollected) {
+  VideoQualityAnalyzer analyzer;
+  {
+    PeerScenario s(*test_info_);
+    auto caller = s.CreateClient(PeerScenarioClient::Config());
+    auto callee = s.CreateClient(PeerScenarioClient::Config());
+    PeerScenarioClient::VideoSendTrackConfig video_conf;
+    video_conf.generator.squares_video->framerate = 20;
+    auto video = caller->CreateVideo("VIDEO", video_conf);
+    auto link_builder = s.net()->NodeBuilder().delay_ms(100).capacity_kbps(600);
+    s.AttachVideoQualityAnalyzer(&analyzer, video.track.get(), callee);
+    s.SimpleConnection(caller, callee, {link_builder.Build().node},
+                       {link_builder.Build().node});
+    s.ProcessMessages(TimeDelta::Seconds(2));
+    // Exit scope to ensure that there's no pending tasks reporting to analyzer.
+  }
+
+  // We expect ca 40 frames to be produced, but to avoid flakiness on slow
+  // machines we only test for 10.
+  EXPECT_GT(analyzer.stats().render.count, 10);
+  EXPECT_GT(analyzer.stats().psnr_with_freeze.Mean(), 20);
+}
+
+}  // namespace test
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/test/peer_scenario/tests/remote_estimate_test.cc b/third_party/libwebrtc/test/peer_scenario/tests/remote_estimate_test.cc
new file mode 100644
index 0000000000..2dfbfdd3c9
--- /dev/null
+++ b/third_party/libwebrtc/test/peer_scenario/tests/remote_estimate_test.cc
@@ -0,0 +1,112 @@
+/*
+ *  Copyright (c) 2019 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 "modules/rtp_rtcp/include/rtp_header_extension_map.h"
+#include "modules/rtp_rtcp/source/rtp_header_extensions.h"
+#include "modules/rtp_rtcp/source/rtp_packet.h"
+#include "modules/rtp_rtcp/source/rtp_util.h"
+#include "pc/media_session.h"
+#include "pc/session_description.h"
+#include "test/field_trial.h"
+#include "test/gtest.h"
+#include "test/peer_scenario/peer_scenario.h"
+
+namespace webrtc {
+namespace test {
+namespace {
+RtpHeaderExtensionMap AudioExtensions(
+    const SessionDescriptionInterface& session) {
+  auto* audio_desc =
+      cricket::GetFirstAudioContentDescription(session.description());
+  return RtpHeaderExtensionMap(audio_desc->rtp_header_extensions());
+}
+
+}  // namespace
+
+TEST(RemoteEstimateEndToEnd, OfferedCapabilityIsInAnswer) {
+  PeerScenario s(*test_info_);
+
+  auto* caller = s.CreateClient(PeerScenarioClient::Config());
+  auto* callee = s.CreateClient(PeerScenarioClient::Config());
+
+  auto send_link = {s.net()->NodeBuilder().Build().node};
+  auto ret_link = {s.net()->NodeBuilder().Build().node};
+
+  s.net()->CreateRoute(caller->endpoint(), send_link, callee->endpoint());
+  s.net()->CreateRoute(callee->endpoint(), ret_link, caller->endpoint());
+
+  auto signaling = s.ConnectSignaling(caller, callee, send_link, ret_link);
+  caller->CreateVideo("VIDEO", PeerScenarioClient::VideoSendTrackConfig());
+  std::atomic<bool> offer_exchange_done(false);
+  signaling.NegotiateSdp(
+      [](SessionDescriptionInterface* offer) {
+        for (auto& cont : offer->description()->contents()) {
+          cont.media_description()->set_remote_estimate(true);
+        }
+      },
+      [&](const SessionDescriptionInterface& answer) {
+        for (auto& cont : answer.description()->contents()) {
+          EXPECT_TRUE(cont.media_description()->remote_estimate());
+        }
+        offer_exchange_done = true;
+      });
+  RTC_CHECK(s.WaitAndProcess(&offer_exchange_done));
+}
+
+TEST(RemoteEstimateEndToEnd, AudioUsesAbsSendTimeExtension) {
+  // Defined before PeerScenario so it gets destructed after, to avoid use after free.
+  std::atomic<bool> received_abs_send_time(false);
+  PeerScenario s(*test_info_);
+
+  auto* caller = s.CreateClient(PeerScenarioClient::Config());
+  auto* callee = s.CreateClient(PeerScenarioClient::Config());
+
+  auto send_node = s.net()->NodeBuilder().Build().node;
+  auto ret_node = s.net()->NodeBuilder().Build().node;
+
+  s.net()->CreateRoute(caller->endpoint(), {send_node}, callee->endpoint());
+  s.net()->CreateRoute(callee->endpoint(), {ret_node}, caller->endpoint());
+
+  auto signaling = s.ConnectSignaling(caller, callee, {send_node}, {ret_node});
+  caller->CreateAudio("AUDIO", cricket::AudioOptions());
+  signaling.StartIceSignaling();
+  RtpHeaderExtensionMap extension_map;
+  std::atomic<bool> offer_exchange_done(false);
+  signaling.NegotiateSdp(
+      [&extension_map](SessionDescriptionInterface* offer) {
+        extension_map = AudioExtensions(*offer);
+        EXPECT_TRUE(extension_map.IsRegistered(kRtpExtensionAbsoluteSendTime));
+      },
+      [&](const SessionDescriptionInterface& answer) {
+        EXPECT_TRUE(AudioExtensions(answer).IsRegistered(
+            kRtpExtensionAbsoluteSendTime));
+        offer_exchange_done = true;
+      });
+  RTC_CHECK(s.WaitAndProcess(&offer_exchange_done));
+  send_node->router()->SetWatcher(
+      [extension_map, &received_abs_send_time](const EmulatedIpPacket& packet) {
+        // The dummy packets used by the fake signaling are filled with 0. We
+        // want to ignore those and we can do that on the basis that the first
+        // byte of RTP packets are guaranteed to not be 0.
+        RtpPacket rtp_packet(&extension_map);
+        // TODO(bugs.webrtc.org/14525): Look why there are RTP packets with
+        // payload 72 or 73 (these don't have the RTP AbsoluteSendTime
+        // Extension).
+        if (rtp_packet.Parse(packet.data) && rtp_packet.PayloadType() == 111) {
+          EXPECT_TRUE(rtp_packet.HasExtension<AbsoluteSendTime>());
+          received_abs_send_time = true;
+        }
+      });
+  RTC_CHECK(s.WaitAndProcess(&received_abs_send_time));
+  caller->pc()->Close();
+  callee->pc()->Close();
+}
+}  // namespace test
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/test/peer_scenario/tests/unsignaled_stream_test.cc b/third_party/libwebrtc/test/peer_scenario/tests/unsignaled_stream_test.cc
new file mode 100644
index 0000000000..4f478b4b2a
--- /dev/null
+++ b/third_party/libwebrtc/test/peer_scenario/tests/unsignaled_stream_test.cc
@@ -0,0 +1,270 @@
+/*
+ *  Copyright (c) 2020 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 "media/base/stream_params.h"
+#include "modules/rtp_rtcp/source/byte_io.h"
+#include "modules/rtp_rtcp/source/rtp_util.h"
+#include "pc/media_session.h"
+#include "pc/session_description.h"
+#include "test/field_trial.h"
+#include "test/gmock.h"
+#include "test/gtest.h"
+#include "test/peer_scenario/peer_scenario.h"
+
+namespace webrtc {
+namespace test {
+namespace {
+
+enum class MidTestConfiguration {
+  // Legacy endpoint setup where PT demuxing is used.
+  kMidNotNegotiated,
+  // MID is negotiated but missing from packets. PT demuxing is disabled, so
+  // SSRCs have to be added to the SDP for WebRTC to forward packets correctly.
+  // Happens when client is spec compliant but the SFU isn't. Popular legacy.
+  kMidNegotiatedButMissingFromPackets,
+  // Fully spec-compliant: MID is present so we can safely drop packets with
+  // unknown MIDs.
+  kMidNegotiatedAndPresentInPackets,
+};
+
+// Gives the parameterized test a readable suffix.
+std::string TestParametersMidTestConfigurationToString(
+    testing::TestParamInfo<MidTestConfiguration> info) {
+  switch (info.param) {
+    case MidTestConfiguration::kMidNotNegotiated:
+      return "MidNotNegotiated";
+    case MidTestConfiguration::kMidNegotiatedButMissingFromPackets:
+      return "MidNegotiatedButMissingFromPackets";
+    case MidTestConfiguration::kMidNegotiatedAndPresentInPackets:
+      return "MidNegotiatedAndPresentInPackets";
+  }
+}
+
+class FrameObserver : public rtc::VideoSinkInterface<VideoFrame> {
+ public:
+  FrameObserver() : frame_observed_(false) {}
+  void OnFrame(const VideoFrame&) override { frame_observed_ = true; }
+
+  std::atomic<bool> frame_observed_;
+};
+
+uint32_t get_ssrc(SessionDescriptionInterface* offer, size_t track_index) {
+  EXPECT_LT(track_index, offer->description()->contents().size());
+  return offer->description()
+      ->contents()[track_index]
+      .media_description()
+      ->streams()[0]
+      .ssrcs[0];
+}
+
+void set_ssrc(SessionDescriptionInterface* offer, size_t index, uint32_t ssrc) {
+  EXPECT_LT(index, offer->description()->contents().size());
+  cricket::StreamParams& new_stream_params = offer->description()
+                                                 ->contents()[index]
+                                                 .media_description()
+                                                 ->mutable_streams()[0];
+  new_stream_params.ssrcs[0] = ssrc;
+  new_stream_params.ssrc_groups[0].ssrcs[0] = ssrc;
+}
+
+}  // namespace
+
+class UnsignaledStreamTest
+    : public ::testing::Test,
+      public ::testing::WithParamInterface<MidTestConfiguration> {};
+
+TEST_P(UnsignaledStreamTest, ReplacesUnsignaledStreamOnCompletedSignaling) {
+  // This test covers a scenario that might occur if a remote client starts
+  // sending media packets before negotiation has completed. Depending on setup,
+  // these packets either get dropped or trigger an unsignalled default stream
+  // to be created, and connects that to a default video sink.
+  // In some edge cases using Unified Plan and PT demuxing, the default stream
+  // is create in a different transceiver to where the media SSRC will actually
+  // be used. This test verifies that the default stream is removed properly,
+  // and that packets are demuxed and video frames reach the desired sink.
+  const MidTestConfiguration kMidTestConfiguration = GetParam();
+
+  // Defined before PeerScenario so it gets destructed after, to avoid use after
+  // free.
+  PeerScenario s(*::testing::UnitTest::GetInstance()->current_test_info());
+
+  PeerScenarioClient::Config config = PeerScenarioClient::Config();
+  // Disable encryption so that we can inject a fake early media packet without
+  // triggering srtp failures.
+  config.disable_encryption = true;
+  auto* caller = s.CreateClient(config);
+  auto* callee = s.CreateClient(config);
+
+  auto send_node = s.net()->NodeBuilder().Build().node;
+  auto ret_node = s.net()->NodeBuilder().Build().node;
+
+  s.net()->CreateRoute(caller->endpoint(), {send_node}, callee->endpoint());
+  s.net()->CreateRoute(callee->endpoint(), {ret_node}, caller->endpoint());
+
+  auto signaling = s.ConnectSignaling(caller, callee, {send_node}, {ret_node});
+  PeerScenarioClient::VideoSendTrackConfig video_conf;
+  video_conf.generator.squares_video->framerate = 15;
+
+  auto first_track = caller->CreateVideo("VIDEO", video_conf);
+  FrameObserver first_sink;
+  callee->AddVideoReceiveSink(first_track.track->id(), &first_sink);
+
+  signaling.StartIceSignaling();
+  std::atomic<bool> offer_exchange_done(false);
+  std::atomic<bool> got_unsignaled_packet(false);
+
+  // We will capture the media ssrc of the first added stream, and preemptively
+  // inject a new media packet using a different ssrc. What happens depends on
+  // the test configuration.
+  //
+  // MidTestConfiguration::kMidNotNegotiated:
+  // - MID is not negotiated which means PT-based demuxing is enabled. Because
+  //   the packets have no MID, the second ssrc packet gets forwarded to the
+  //   first m= section. This will create a "default stream" for the second ssrc
+  //   and connect it to the default video sink (not set in this test). The test
+  //   verifies we can recover from this when we later get packets for the first
+  //   ssrc.
+  //
+  // MidTestConfiguration::kMidNegotiatedButMissingFromPackets:
+  // - MID is negotiated wich means PT-based demuxing is disabled. Because we
+  //   modify the packets not to contain the MID anyway (simulating a legacy SFU
+  //   that does not negotiate properly) unknown SSRCs are dropped but do not
+  //   otherwise cause any issues.
+  //
+  // MidTestConfiguration::kMidNegotiatedAndPresentInPackets:
+  // - MID is negotiated which means PT-based demuxing is enabled. In this case
+  //   the packets have the MID so they either get forwarded or dropped
+  //   depending on if the MID is known. The spec-compliant way is also the most
+  //   straight-forward one.
+
+  uint32_t first_ssrc = 0;
+  uint32_t second_ssrc = 0;
+  absl::optional<int> mid_header_extension_id = absl::nullopt;
+
+  signaling.NegotiateSdp(
+      /* munge_sdp = */
+      [&](SessionDescriptionInterface* offer) {
+        // Obtain the MID header extension ID and if we want the
+        // MidTestConfiguration::kMidNotNegotiated setup then we remove the MID
+        // header extension through SDP munging (otherwise SDP is not modified).
+        for (cricket::ContentInfo& content_info :
+             offer->description()->contents()) {
+          std::vector<RtpExtension> header_extensions =
+              content_info.media_description()->rtp_header_extensions();
+          for (auto it = header_extensions.begin();
+               it != header_extensions.end(); ++it) {
+            if (it->uri == RtpExtension::kMidUri) {
+              // MID header extension found!
+              mid_header_extension_id = it->id;
+              if (kMidTestConfiguration ==
+                  MidTestConfiguration::kMidNotNegotiated) {
+                // Munge away the extension.
+                header_extensions.erase(it);
+              }
+              break;
+            }
+          }
+          content_info.media_description()->set_rtp_header_extensions(
+              std::move(header_extensions));
+        }
+        ASSERT_TRUE(mid_header_extension_id.has_value());
+      },
+      /* modify_sdp = */
+      [&](SessionDescriptionInterface* offer) {
+        first_ssrc = get_ssrc(offer, 0);
+        second_ssrc = first_ssrc + 1;
+
+        send_node->router()->SetWatcher([&](const EmulatedIpPacket& packet) {
+          if (IsRtpPacket(packet.data) &&
+              ByteReader<uint32_t>::ReadBigEndian(&(packet.cdata()[8])) ==
+                  first_ssrc &&
+              !got_unsignaled_packet) {
+            // Parse packet and modify the SSRC to simulate a second m=
+            // section that has not been negotiated yet.
+            std::vector<RtpExtension> extensions;
+            extensions.emplace_back(RtpExtension::kMidUri,
+                                    mid_header_extension_id.value());
+            RtpHeaderExtensionMap extensions_map(extensions);
+            RtpPacket parsed_packet;
+            parsed_packet.IdentifyExtensions(extensions_map);
+            ASSERT_TRUE(parsed_packet.Parse(packet.data));
+            parsed_packet.SetSsrc(second_ssrc);
+            // The MID extension is present if and only if it was negotiated.
+            // If present, we either want to remove it or modify it depending
+            // on setup.
+            switch (kMidTestConfiguration) {
+              case MidTestConfiguration::kMidNotNegotiated:
+                EXPECT_FALSE(parsed_packet.HasExtension<RtpMid>());
+                break;
+              case MidTestConfiguration::kMidNegotiatedButMissingFromPackets:
+                EXPECT_TRUE(parsed_packet.HasExtension<RtpMid>());
+                ASSERT_TRUE(parsed_packet.RemoveExtension(RtpMid::kId));
+                break;
+              case MidTestConfiguration::kMidNegotiatedAndPresentInPackets:
+                EXPECT_TRUE(parsed_packet.HasExtension<RtpMid>());
+                // The simulated second m= section would have a different MID.
+                // If we don't modify it here then `second_ssrc` would end up
+                // being mapped to the first m= section which would cause SSRC
+                // conflicts if we later add the same SSRC to a second m=
+                // section. Hidden assumption: first m= section does not use
+                // MID:1.
+                ASSERT_TRUE(parsed_packet.SetExtension<RtpMid>("1"));
+                break;
+            }
+            // Inject the modified packet.
+            rtc::CopyOnWriteBuffer updated_buffer = parsed_packet.Buffer();
+            EmulatedIpPacket updated_packet(
+                packet.from, packet.to, updated_buffer, packet.arrival_time);
+            send_node->OnPacketReceived(std::move(updated_packet));
+            got_unsignaled_packet = true;
+          }
+        });
+      },
+      [&](const SessionDescriptionInterface& answer) {
+        EXPECT_EQ(answer.description()->contents().size(), 1u);
+        offer_exchange_done = true;
+      });
+  EXPECT_TRUE(s.WaitAndProcess(&offer_exchange_done));
+  EXPECT_TRUE(s.WaitAndProcess(&got_unsignaled_packet));
+  EXPECT_TRUE(s.WaitAndProcess(&first_sink.frame_observed_));
+
+  auto second_track = caller->CreateVideo("VIDEO2", video_conf);
+  FrameObserver second_sink;
+  callee->AddVideoReceiveSink(second_track.track->id(), &second_sink);
+
+  // Create a second video stream, munge the sdp to force it to use our fake
+  // early media ssrc.
+  offer_exchange_done = false;
+  signaling.NegotiateSdp(
+      /* munge_sdp = */
+      [&](SessionDescriptionInterface* offer) {
+        set_ssrc(offer, 1, second_ssrc);
+      },
+      /* modify_sdp = */ {},
+      [&](const SessionDescriptionInterface& answer) {
+        EXPECT_EQ(answer.description()->contents().size(), 2u);
+        offer_exchange_done = true;
+      });
+  EXPECT_TRUE(s.WaitAndProcess(&offer_exchange_done));
+  EXPECT_TRUE(s.WaitAndProcess(&second_sink.frame_observed_));
+  caller->pc()->Close();
+  callee->pc()->Close();
+}
+
+INSTANTIATE_TEST_SUITE_P(
+    All,
+    UnsignaledStreamTest,
+    ::testing::Values(MidTestConfiguration::kMidNotNegotiated,
+                      MidTestConfiguration::kMidNegotiatedButMissingFromPackets,
+                      MidTestConfiguration::kMidNegotiatedAndPresentInPackets),
+    TestParametersMidTestConfigurationToString);
+
+}  // namespace test
+}  // namespace webrtc