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

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

2 files changed, 747 insertions, 0 deletions

diff --git a/third_party/libwebrtc/test/pc/e2e/sdp/sdp_changer.cc b/third_party/libwebrtc/test/pc/e2e/sdp/sdp_changer.cc
new file mode 100644
index 0000000000..af55f29175
--- /dev/null
+++ b/third_party/libwebrtc/test/pc/e2e/sdp/sdp_changer.cc
@@ -0,0 +1,601 @@
+/*
+ *  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/pc/e2e/sdp/sdp_changer.h"
+
+#include <utility>
+
+#include "absl/memory/memory.h"
+#include "api/jsep_session_description.h"
+#include "api/test/pclf/media_configuration.h"
+#include "media/base/media_constants.h"
+#include "p2p/base/p2p_constants.h"
+#include "pc/sdp_utils.h"
+#include "rtc_base/strings/string_builder.h"
+
+namespace webrtc {
+namespace webrtc_pc_e2e {
+namespace {
+
+std::string CodecRequiredParamsToString(
+    const std::map<std::string, std::string>& codec_required_params) {
+  rtc::StringBuilder out;
+  for (const auto& entry : codec_required_params) {
+    out << entry.first << "=" << entry.second << ";";
+  }
+  return out.str();
+}
+
+std::string SupportedCodecsToString(
+    rtc::ArrayView<const RtpCodecCapability> supported_codecs) {
+  rtc::StringBuilder out;
+  for (const auto& codec : supported_codecs) {
+    out << codec.name;
+    if (!codec.parameters.empty()) {
+      out << "(";
+      for (const auto& param : codec.parameters) {
+        out << param.first << "=" << param.second << ";";
+      }
+      out << ")";
+    }
+    out << "; ";
+  }
+  return out.str();
+}
+
+}  // namespace
+
+std::vector<RtpCodecCapability> FilterVideoCodecCapabilities(
+    rtc::ArrayView<const VideoCodecConfig> video_codecs,
+    bool use_rtx,
+    bool use_ulpfec,
+    bool use_flexfec,
+    rtc::ArrayView<const RtpCodecCapability> supported_codecs) {
+  std::vector<RtpCodecCapability> output_codecs;
+  // Find requested codecs among supported and add them to output in the order
+  // they were requested.
+  for (auto& codec_request : video_codecs) {
+    size_t size_before = output_codecs.size();
+    for (auto& codec : supported_codecs) {
+      if (codec.name != codec_request.name) {
+        continue;
+      }
+      bool parameters_matched = true;
+      for (const auto& item : codec_request.required_params) {
+        auto it = codec.parameters.find(item.first);
+        if (it == codec.parameters.end()) {
+          parameters_matched = false;
+          break;
+        }
+        if (item.second != it->second) {
+          parameters_matched = false;
+          break;
+        }
+      }
+      if (parameters_matched) {
+        output_codecs.push_back(codec);
+      }
+    }
+    RTC_CHECK_GT(output_codecs.size(), size_before)
+        << "Codec with name=" << codec_request.name << " and params {"
+        << CodecRequiredParamsToString(codec_request.required_params)
+        << "} is unsupported for this peer connection. Supported codecs are: "
+        << SupportedCodecsToString(supported_codecs);
+  }
+
+  // Add required FEC and RTX codecs to output.
+  for (auto& codec : supported_codecs) {
+    if (codec.name == cricket::kRtxCodecName && use_rtx) {
+      output_codecs.push_back(codec);
+    } else if (codec.name == cricket::kFlexfecCodecName && use_flexfec) {
+      output_codecs.push_back(codec);
+    } else if ((codec.name == cricket::kRedCodecName ||
+                codec.name == cricket::kUlpfecCodecName) &&
+               use_ulpfec) {
+      // Red and ulpfec should be enabled or disabled together.
+      output_codecs.push_back(codec);
+    }
+  }
+  return output_codecs;
+}
+
+// If offer has no simulcast video sections - do nothing.
+//
+// If offer has simulcast video sections - for each section creates
+// SimulcastSectionInfo and put it into `context_`.
+void SignalingInterceptor::FillSimulcastContext(
+    SessionDescriptionInterface* offer) {
+  for (auto& content : offer->description()->contents()) {
+    cricket::MediaContentDescription* media_desc = content.media_description();
+    if (media_desc->type() != cricket::MediaType::MEDIA_TYPE_VIDEO) {
+      continue;
+    }
+    if (media_desc->HasSimulcast()) {
+      // We support only single stream simulcast sections with rids.
+      RTC_CHECK_EQ(media_desc->mutable_streams().size(), 1);
+      RTC_CHECK(media_desc->mutable_streams()[0].has_rids());
+
+      // Create SimulcastSectionInfo for this video section.
+      SimulcastSectionInfo info(content.mid(), content.type,
+                                media_desc->mutable_streams()[0].rids());
+
+      // Set new rids basing on created SimulcastSectionInfo.
+      std::vector<cricket::RidDescription> rids;
+      cricket::SimulcastDescription simulcast_description;
+      for (std::string& rid : info.rids) {
+        rids.emplace_back(rid, cricket::RidDirection::kSend);
+        simulcast_description.send_layers().AddLayer(
+            cricket::SimulcastLayer(rid, false));
+      }
+      media_desc->mutable_streams()[0].set_rids(rids);
+      media_desc->set_simulcast_description(simulcast_description);
+
+      info.simulcast_description = media_desc->simulcast_description();
+      for (const auto& extension : media_desc->rtp_header_extensions()) {
+        if (extension.uri == RtpExtension::kMidUri) {
+          info.mid_extension = extension;
+        } else if (extension.uri == RtpExtension::kRidUri) {
+          info.rid_extension = extension;
+        } else if (extension.uri == RtpExtension::kRepairedRidUri) {
+          info.rrid_extension = extension;
+        }
+      }
+      RTC_CHECK_NE(info.rid_extension.id, 0);
+      RTC_CHECK_NE(info.mid_extension.id, 0);
+      bool transport_description_found = false;
+      for (auto& transport_info : offer->description()->transport_infos()) {
+        if (transport_info.content_name == info.mid) {
+          info.transport_description = transport_info.description;
+          transport_description_found = true;
+          break;
+        }
+      }
+      RTC_CHECK(transport_description_found);
+
+      context_.AddSimulcastInfo(info);
+    }
+  }
+}
+
+LocalAndRemoteSdp SignalingInterceptor::PatchOffer(
+    std::unique_ptr<SessionDescriptionInterface> offer,
+    const VideoCodecConfig& first_codec) {
+  for (auto& content : offer->description()->contents()) {
+    context_.mids_order.push_back(content.mid());
+    cricket::MediaContentDescription* media_desc = content.media_description();
+    if (media_desc->type() != cricket::MediaType::MEDIA_TYPE_VIDEO) {
+      continue;
+    }
+    if (content.media_description()->streams().empty()) {
+      // It means that this media section describes receive only media section
+      // in SDP.
+      RTC_CHECK_EQ(content.media_description()->direction(),
+                   RtpTransceiverDirection::kRecvOnly);
+      continue;
+    }
+    media_desc->set_conference_mode(params_.use_conference_mode);
+  }
+
+  if (!params_.stream_label_to_simulcast_streams_count.empty()) {
+    // Because simulcast enabled `params_.video_codecs` has only 1 element.
+    if (first_codec.name == cricket::kVp8CodecName) {
+      return PatchVp8Offer(std::move(offer));
+    }
+
+    if (first_codec.name == cricket::kVp9CodecName) {
+      return PatchVp9Offer(std::move(offer));
+    }
+  }
+
+  auto offer_for_remote = CloneSessionDescription(offer.get());
+  return LocalAndRemoteSdp(std::move(offer), std::move(offer_for_remote));
+}
+
+LocalAndRemoteSdp SignalingInterceptor::PatchVp8Offer(
+    std::unique_ptr<SessionDescriptionInterface> offer) {
+  FillSimulcastContext(offer.get());
+  if (!context_.HasSimulcast()) {
+    auto offer_for_remote = CloneSessionDescription(offer.get());
+    return LocalAndRemoteSdp(std::move(offer), std::move(offer_for_remote));
+  }
+
+  // Clone original offer description. We mustn't access original offer after
+  // this point.
+  std::unique_ptr<cricket::SessionDescription> desc =
+      offer->description()->Clone();
+
+  for (auto& info : context_.simulcast_infos) {
+    // For each simulcast section we have to perform:
+    //   1. Swap MID and RID header extensions
+    //   2. Remove RIDs from streams and remove SimulcastDescription
+    //   3. For each RID duplicate media section
+    cricket::ContentInfo* simulcast_content = desc->GetContentByName(info.mid);
+
+    // Now we need to prepare common prototype for "m=video" sections, in which
+    // single simulcast section will be converted. Do it before removing content
+    // because otherwise description will be deleted.
+    std::unique_ptr<cricket::MediaContentDescription> prototype_media_desc =
+        simulcast_content->media_description()->Clone();
+
+    // Remove simulcast video section from offer.
+    RTC_CHECK(desc->RemoveContentByName(simulcast_content->mid()));
+    // Clear `simulcast_content`, because now it is pointing to removed object.
+    simulcast_content = nullptr;
+
+    // Swap mid and rid extensions, so remote peer will understand rid as mid.
+    // Also remove rid extension.
+    std::vector<webrtc::RtpExtension> extensions =
+        prototype_media_desc->rtp_header_extensions();
+    for (auto ext_it = extensions.begin(); ext_it != extensions.end();) {
+      if (ext_it->uri == RtpExtension::kRidUri) {
+        // We don't need rid extension for remote peer.
+        ext_it = extensions.erase(ext_it);
+        continue;
+      }
+      if (ext_it->uri == RtpExtension::kRepairedRidUri) {
+        // We don't support RTX in simulcast.
+        ext_it = extensions.erase(ext_it);
+        continue;
+      }
+      if (ext_it->uri == RtpExtension::kMidUri) {
+        ext_it->id = info.rid_extension.id;
+      }
+      ++ext_it;
+    }
+
+    prototype_media_desc->ClearRtpHeaderExtensions();
+    prototype_media_desc->set_rtp_header_extensions(extensions);
+
+    // We support only single stream inside video section with simulcast
+    RTC_CHECK_EQ(prototype_media_desc->mutable_streams().size(), 1);
+    // This stream must have rids.
+    RTC_CHECK(prototype_media_desc->mutable_streams()[0].has_rids());
+
+    // Remove rids and simulcast description from media description.
+    prototype_media_desc->mutable_streams()[0].set_rids({});
+    prototype_media_desc->set_simulcast_description(
+        cricket::SimulcastDescription());
+
+    // For each rid add separate video section.
+    for (std::string& rid : info.rids) {
+      desc->AddContent(rid, info.media_protocol_type,
+                       prototype_media_desc->Clone());
+    }
+  }
+
+  // Now we need to add bundle line to have all media bundled together.
+  cricket::ContentGroup bundle_group(cricket::GROUP_TYPE_BUNDLE);
+  for (auto& content : desc->contents()) {
+    bundle_group.AddContentName(content.mid());
+  }
+  if (desc->HasGroup(cricket::GROUP_TYPE_BUNDLE)) {
+    desc->RemoveGroupByName(cricket::GROUP_TYPE_BUNDLE);
+  }
+  desc->AddGroup(bundle_group);
+
+  // Update transport_infos to add TransportInfo for each new media section.
+  std::vector<cricket::TransportInfo> transport_infos = desc->transport_infos();
+  transport_infos.erase(std::remove_if(
+      transport_infos.begin(), transport_infos.end(),
+      [this](const cricket::TransportInfo& ti) {
+        // Remove transport infos that correspond to simulcast video sections.
+        return context_.simulcast_infos_by_mid.find(ti.content_name) !=
+               context_.simulcast_infos_by_mid.end();
+      }));
+  for (auto& info : context_.simulcast_infos) {
+    for (auto& rid : info.rids) {
+      transport_infos.emplace_back(rid, info.transport_description);
+    }
+  }
+  desc->set_transport_infos(transport_infos);
+
+  // Create patched offer.
+  auto patched_offer =
+      std::make_unique<JsepSessionDescription>(SdpType::kOffer);
+  patched_offer->Initialize(std::move(desc), offer->session_id(),
+                            offer->session_version());
+  return LocalAndRemoteSdp(std::move(offer), std::move(patched_offer));
+}
+
+LocalAndRemoteSdp SignalingInterceptor::PatchVp9Offer(
+    std::unique_ptr<SessionDescriptionInterface> offer) {
+  rtc::UniqueRandomIdGenerator ssrcs_generator;
+  for (auto& content : offer->description()->contents()) {
+    for (auto& stream : content.media_description()->streams()) {
+      for (auto& ssrc : stream.ssrcs) {
+        ssrcs_generator.AddKnownId(ssrc);
+      }
+    }
+  }
+
+  for (auto& content : offer->description()->contents()) {
+    if (content.media_description()->type() !=
+        cricket::MediaType::MEDIA_TYPE_VIDEO) {
+      // We are interested in only video tracks
+      continue;
+    }
+    if (content.media_description()->direction() ==
+        RtpTransceiverDirection::kRecvOnly) {
+      // If direction is receive only, then there is no media in this track from
+      // sender side, so we needn't to do anything with this track.
+      continue;
+    }
+    RTC_CHECK_EQ(content.media_description()->streams().size(), 1);
+    cricket::StreamParams& stream =
+        content.media_description()->mutable_streams()[0];
+    RTC_CHECK_EQ(stream.stream_ids().size(), 2)
+        << "Expected 2 stream ids in video stream: 1st - sync_group, 2nd - "
+           "unique label";
+    std::string stream_label = stream.stream_ids()[1];
+
+    auto it =
+        params_.stream_label_to_simulcast_streams_count.find(stream_label);
+    if (it == params_.stream_label_to_simulcast_streams_count.end()) {
+      continue;
+    }
+    int svc_layers_count = it->second;
+
+    RTC_CHECK(stream.has_ssrc_groups()) << "Only SVC with RTX is supported";
+    RTC_CHECK_EQ(stream.ssrc_groups.size(), 1)
+        << "Too many ssrc groups in the track";
+    std::vector<uint32_t> primary_ssrcs;
+    stream.GetPrimarySsrcs(&primary_ssrcs);
+    RTC_CHECK(primary_ssrcs.size() == 1);
+    for (int i = 1; i < svc_layers_count; ++i) {
+      uint32_t ssrc = ssrcs_generator.GenerateId();
+      primary_ssrcs.push_back(ssrc);
+      stream.add_ssrc(ssrc);
+      stream.AddFidSsrc(ssrc, ssrcs_generator.GenerateId());
+    }
+    stream.ssrc_groups.push_back(
+        cricket::SsrcGroup(cricket::kSimSsrcGroupSemantics, primary_ssrcs));
+  }
+  auto offer_for_remote = CloneSessionDescription(offer.get());
+  return LocalAndRemoteSdp(std::move(offer), std::move(offer_for_remote));
+}
+
+LocalAndRemoteSdp SignalingInterceptor::PatchAnswer(
+    std::unique_ptr<SessionDescriptionInterface> answer,
+    const VideoCodecConfig& first_codec) {
+  for (auto& content : answer->description()->contents()) {
+    cricket::MediaContentDescription* media_desc = content.media_description();
+    if (media_desc->type() != cricket::MediaType::MEDIA_TYPE_VIDEO) {
+      continue;
+    }
+    if (content.media_description()->direction() !=
+        RtpTransceiverDirection::kRecvOnly) {
+      continue;
+    }
+    media_desc->set_conference_mode(params_.use_conference_mode);
+  }
+
+  if (!params_.stream_label_to_simulcast_streams_count.empty()) {
+    // Because simulcast enabled `params_.video_codecs` has only 1 element.
+    if (first_codec.name == cricket::kVp8CodecName) {
+      return PatchVp8Answer(std::move(answer));
+    }
+
+    if (first_codec.name == cricket::kVp9CodecName) {
+      return PatchVp9Answer(std::move(answer));
+    }
+  }
+
+  auto answer_for_remote = CloneSessionDescription(answer.get());
+  return LocalAndRemoteSdp(std::move(answer), std::move(answer_for_remote));
+}
+
+LocalAndRemoteSdp SignalingInterceptor::PatchVp8Answer(
+    std::unique_ptr<SessionDescriptionInterface> answer) {
+  if (!context_.HasSimulcast()) {
+    auto answer_for_remote = CloneSessionDescription(answer.get());
+    return LocalAndRemoteSdp(std::move(answer), std::move(answer_for_remote));
+  }
+
+  std::unique_ptr<cricket::SessionDescription> desc =
+      answer->description()->Clone();
+
+  for (auto& info : context_.simulcast_infos) {
+    cricket::ContentInfo* simulcast_content =
+        desc->GetContentByName(info.rids[0]);
+    RTC_CHECK(simulcast_content);
+
+    // Get media description, which will be converted to simulcast answer.
+    std::unique_ptr<cricket::MediaContentDescription> media_desc =
+        simulcast_content->media_description()->Clone();
+    // Set `simulcast_content` to nullptr, because then it will be removed, so
+    // it will point to deleted object.
+    simulcast_content = nullptr;
+
+    // Remove separate media sections for simulcast streams.
+    for (auto& rid : info.rids) {
+      RTC_CHECK(desc->RemoveContentByName(rid));
+    }
+
+    // Patch `media_desc` to make it simulcast answer description.
+    // Restore mid/rid rtp header extensions
+    std::vector<webrtc::RtpExtension> extensions =
+        media_desc->rtp_header_extensions();
+    // First remove existing rid/mid header extensions.
+    extensions.erase(std::remove_if(extensions.begin(), extensions.end(),
+                                    [](const webrtc::RtpExtension& e) {
+                                      return e.uri == RtpExtension::kMidUri ||
+                                             e.uri == RtpExtension::kRidUri ||
+                                             e.uri ==
+                                                 RtpExtension::kRepairedRidUri;
+                                    }));
+
+    // Then add right ones.
+    extensions.push_back(info.mid_extension);
+    extensions.push_back(info.rid_extension);
+    // extensions.push_back(info.rrid_extension);
+    media_desc->ClearRtpHeaderExtensions();
+    media_desc->set_rtp_header_extensions(extensions);
+
+    // Add StreamParams with rids for receive.
+    RTC_CHECK_EQ(media_desc->mutable_streams().size(), 0);
+    std::vector<cricket::RidDescription> rids;
+    for (auto& rid : info.rids) {
+      rids.emplace_back(rid, cricket::RidDirection::kReceive);
+    }
+    cricket::StreamParams stream_params;
+    stream_params.set_rids(rids);
+    media_desc->mutable_streams().push_back(stream_params);
+
+    // Restore SimulcastDescription. It should correspond to one from offer,
+    // but it have to have receive layers instead of send. So we need to put
+    // send layers from offer to receive layers in answer.
+    cricket::SimulcastDescription simulcast_description;
+    for (const auto& layer : info.simulcast_description.send_layers()) {
+      simulcast_description.receive_layers().AddLayerWithAlternatives(layer);
+    }
+    media_desc->set_simulcast_description(simulcast_description);
+
+    // Add simulcast media section.
+    desc->AddContent(info.mid, info.media_protocol_type, std::move(media_desc));
+  }
+
+  desc = RestoreMediaSectionsOrder(std::move(desc));
+
+  // Now we need to add bundle line to have all media bundled together.
+  cricket::ContentGroup bundle_group(cricket::GROUP_TYPE_BUNDLE);
+  for (auto& content : desc->contents()) {
+    bundle_group.AddContentName(content.mid());
+  }
+  if (desc->HasGroup(cricket::GROUP_TYPE_BUNDLE)) {
+    desc->RemoveGroupByName(cricket::GROUP_TYPE_BUNDLE);
+  }
+  desc->AddGroup(bundle_group);
+
+  // Fix transport_infos: it have to have single info for simulcast section.
+  std::vector<cricket::TransportInfo> transport_infos = desc->transport_infos();
+  std::map<std::string, cricket::TransportDescription>
+      mid_to_transport_description;
+  for (auto info_it = transport_infos.begin();
+       info_it != transport_infos.end();) {
+    auto it = context_.simulcast_infos_by_rid.find(info_it->content_name);
+    if (it != context_.simulcast_infos_by_rid.end()) {
+      // This transport info correspond to some extra added media section.
+      mid_to_transport_description.insert(
+          {it->second->mid, info_it->description});
+      info_it = transport_infos.erase(info_it);
+    } else {
+      ++info_it;
+    }
+  }
+  for (auto& info : context_.simulcast_infos) {
+    transport_infos.emplace_back(info.mid,
+                                 mid_to_transport_description.at(info.mid));
+  }
+  desc->set_transport_infos(transport_infos);
+
+  auto patched_answer =
+      std::make_unique<JsepSessionDescription>(SdpType::kAnswer);
+  patched_answer->Initialize(std::move(desc), answer->session_id(),
+                             answer->session_version());
+  return LocalAndRemoteSdp(std::move(answer), std::move(patched_answer));
+}
+
+std::unique_ptr<cricket::SessionDescription>
+SignalingInterceptor::RestoreMediaSectionsOrder(
+    std::unique_ptr<cricket::SessionDescription> source) {
+  std::unique_ptr<cricket::SessionDescription> out = source->Clone();
+  for (auto& mid : context_.mids_order) {
+    RTC_CHECK(out->RemoveContentByName(mid));
+  }
+  RTC_CHECK_EQ(out->contents().size(), 0);
+  for (auto& mid : context_.mids_order) {
+    cricket::ContentInfo* content = source->GetContentByName(mid);
+    RTC_CHECK(content);
+    out->AddContent(mid, content->type, content->media_description()->Clone());
+  }
+  return out;
+}
+
+LocalAndRemoteSdp SignalingInterceptor::PatchVp9Answer(
+    std::unique_ptr<SessionDescriptionInterface> answer) {
+  auto answer_for_remote = CloneSessionDescription(answer.get());
+  return LocalAndRemoteSdp(std::move(answer), std::move(answer_for_remote));
+}
+
+std::vector<std::unique_ptr<IceCandidateInterface>>
+SignalingInterceptor::PatchOffererIceCandidates(
+    rtc::ArrayView<const IceCandidateInterface* const> candidates) {
+  std::vector<std::unique_ptr<IceCandidateInterface>> out;
+  for (auto* candidate : candidates) {
+    auto simulcast_info_it =
+        context_.simulcast_infos_by_mid.find(candidate->sdp_mid());
+    if (simulcast_info_it != context_.simulcast_infos_by_mid.end()) {
+      // This is candidate for simulcast section, so it should be transformed
+      // into candidates for replicated sections. The sdpMLineIndex is set to
+      // -1 and ignored if the rid is present.
+      for (const std::string& rid : simulcast_info_it->second->rids) {
+        out.push_back(CreateIceCandidate(rid, -1, candidate->candidate()));
+      }
+    } else {
+      out.push_back(CreateIceCandidate(candidate->sdp_mid(),
+                                       candidate->sdp_mline_index(),
+                                       candidate->candidate()));
+    }
+  }
+  RTC_CHECK_GT(out.size(), 0);
+  return out;
+}
+
+std::vector<std::unique_ptr<IceCandidateInterface>>
+SignalingInterceptor::PatchAnswererIceCandidates(
+    rtc::ArrayView<const IceCandidateInterface* const> candidates) {
+  std::vector<std::unique_ptr<IceCandidateInterface>> out;
+  for (auto* candidate : candidates) {
+    auto simulcast_info_it =
+        context_.simulcast_infos_by_rid.find(candidate->sdp_mid());
+    if (simulcast_info_it != context_.simulcast_infos_by_rid.end()) {
+      // This is candidate for replicated section, created from single simulcast
+      // section, so it should be transformed into candidates for simulcast
+      // section.
+      out.push_back(CreateIceCandidate(simulcast_info_it->second->mid, 0,
+                                       candidate->candidate()));
+    } else if (!context_.simulcast_infos_by_rid.empty()) {
+      // When using simulcast and bundle, put everything on the first m-line.
+      out.push_back(CreateIceCandidate("", 0, candidate->candidate()));
+    } else {
+      out.push_back(CreateIceCandidate(candidate->sdp_mid(),
+                                       candidate->sdp_mline_index(),
+                                       candidate->candidate()));
+    }
+  }
+  RTC_CHECK_GT(out.size(), 0);
+  return out;
+}
+
+SignalingInterceptor::SimulcastSectionInfo::SimulcastSectionInfo(
+    const std::string& mid,
+    cricket::MediaProtocolType media_protocol_type,
+    const std::vector<cricket::RidDescription>& rids_desc)
+    : mid(mid), media_protocol_type(media_protocol_type) {
+  for (auto& rid : rids_desc) {
+    rids.push_back(rid.rid);
+  }
+}
+
+void SignalingInterceptor::SignalingContext::AddSimulcastInfo(
+    const SimulcastSectionInfo& info) {
+  simulcast_infos.push_back(info);
+  bool inserted =
+      simulcast_infos_by_mid.insert({info.mid, &simulcast_infos.back()}).second;
+  RTC_CHECK(inserted);
+  for (auto& rid : info.rids) {
+    inserted =
+        simulcast_infos_by_rid.insert({rid, &simulcast_infos.back()}).second;
+    RTC_CHECK(inserted);
+  }
+}
+
+}  // namespace webrtc_pc_e2e
+}  // namespace webrtc
diff --git a/third_party/libwebrtc/test/pc/e2e/sdp/sdp_changer.h b/third_party/libwebrtc/test/pc/e2e/sdp/sdp_changer.h
new file mode 100644
index 0000000000..6f68d03f52
--- /dev/null
+++ b/third_party/libwebrtc/test/pc/e2e/sdp/sdp_changer.h
@@ -0,0 +1,146 @@
+/*
+ *  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_PC_E2E_SDP_SDP_CHANGER_H_
+#define TEST_PC_E2E_SDP_SDP_CHANGER_H_
+
+#include <map>
+#include <string>
+#include <vector>
+
+#include "absl/strings/string_view.h"
+#include "absl/types/optional.h"
+#include "api/array_view.h"
+#include "api/jsep.h"
+#include "api/rtp_parameters.h"
+#include "api/test/pclf/media_configuration.h"
+#include "media/base/rid_description.h"
+#include "pc/session_description.h"
+#include "pc/simulcast_description.h"
+
+namespace webrtc {
+namespace webrtc_pc_e2e {
+
+// Creates list of capabilities, which can be set on RtpTransceiverInterface via
+// RtpTransceiverInterface::SetCodecPreferences(...) to negotiate use of codecs
+// from list of `supported_codecs` which will match `video_codecs`. If flags
+// `ulpfec` or `flexfec` set to true corresponding FEC codec will be added.
+// FEC and RTX codecs will be added after required codecs.
+//
+// All codecs will be added only if they exists in the list of
+// `supported_codecs`. If multiple codecs from this list will match
+// `video_codecs`, then all of them will be added to the output
+// vector and they will be added in the same order, as they were in
+// `supported_codecs`.
+std::vector<RtpCodecCapability> FilterVideoCodecCapabilities(
+    rtc::ArrayView<const VideoCodecConfig> video_codecs,
+    bool use_rtx,
+    bool use_ulpfec,
+    bool use_flexfec,
+    rtc::ArrayView<const RtpCodecCapability> supported_codecs);
+
+struct LocalAndRemoteSdp {
+  LocalAndRemoteSdp(std::unique_ptr<SessionDescriptionInterface> local_sdp,
+                    std::unique_ptr<SessionDescriptionInterface> remote_sdp)
+      : local_sdp(std::move(local_sdp)), remote_sdp(std::move(remote_sdp)) {}
+
+  // Sdp, that should be as local description on the peer, that created it.
+  std::unique_ptr<SessionDescriptionInterface> local_sdp;
+  // Sdp, that should be set as remote description on the peer opposite to the
+  // one, who created it.
+  std::unique_ptr<SessionDescriptionInterface> remote_sdp;
+};
+
+struct PatchingParams {
+  PatchingParams(
+      bool use_conference_mode,
+      std::map<std::string, int> stream_label_to_simulcast_streams_count)
+      : use_conference_mode(use_conference_mode),
+        stream_label_to_simulcast_streams_count(
+            stream_label_to_simulcast_streams_count) {}
+
+  bool use_conference_mode;
+  std::map<std::string, int> stream_label_to_simulcast_streams_count;
+};
+
+class SignalingInterceptor {
+ public:
+  explicit SignalingInterceptor(PatchingParams params) : params_(params) {}
+
+  LocalAndRemoteSdp PatchOffer(
+      std::unique_ptr<SessionDescriptionInterface> offer,
+      const VideoCodecConfig& first_codec);
+  LocalAndRemoteSdp PatchAnswer(
+      std::unique_ptr<SessionDescriptionInterface> answer,
+      const VideoCodecConfig& first_codec);
+
+  std::vector<std::unique_ptr<IceCandidateInterface>> PatchOffererIceCandidates(
+      rtc::ArrayView<const IceCandidateInterface* const> candidates);
+  std::vector<std::unique_ptr<IceCandidateInterface>>
+  PatchAnswererIceCandidates(
+      rtc::ArrayView<const IceCandidateInterface* const> candidates);
+
+ private:
+  // Contains information about simulcast section, that is required to perform
+  // modified offer/answer and ice candidates exchange.
+  struct SimulcastSectionInfo {
+    SimulcastSectionInfo(const std::string& mid,
+                         cricket::MediaProtocolType media_protocol_type,
+                         const std::vector<cricket::RidDescription>& rids_desc);
+
+    const std::string mid;
+    const cricket::MediaProtocolType media_protocol_type;
+    std::vector<std::string> rids;
+    cricket::SimulcastDescription simulcast_description;
+    webrtc::RtpExtension mid_extension;
+    webrtc::RtpExtension rid_extension;
+    webrtc::RtpExtension rrid_extension;
+    cricket::TransportDescription transport_description;
+  };
+
+  struct SignalingContext {
+    SignalingContext() = default;
+    // SignalingContext is not copyable and movable.
+    SignalingContext(SignalingContext&) = delete;
+    SignalingContext& operator=(SignalingContext&) = delete;
+    SignalingContext(SignalingContext&&) = delete;
+    SignalingContext& operator=(SignalingContext&&) = delete;
+
+    void AddSimulcastInfo(const SimulcastSectionInfo& info);
+    bool HasSimulcast() const { return !simulcast_infos.empty(); }
+
+    std::vector<SimulcastSectionInfo> simulcast_infos;
+    std::map<std::string, SimulcastSectionInfo*> simulcast_infos_by_mid;
+    std::map<std::string, SimulcastSectionInfo*> simulcast_infos_by_rid;
+
+    std::vector<std::string> mids_order;
+  };
+
+  LocalAndRemoteSdp PatchVp8Offer(
+      std::unique_ptr<SessionDescriptionInterface> offer);
+  LocalAndRemoteSdp PatchVp9Offer(
+      std::unique_ptr<SessionDescriptionInterface> offer);
+  LocalAndRemoteSdp PatchVp8Answer(
+      std::unique_ptr<SessionDescriptionInterface> answer);
+  LocalAndRemoteSdp PatchVp9Answer(
+      std::unique_ptr<SessionDescriptionInterface> answer);
+
+  void FillSimulcastContext(SessionDescriptionInterface* offer);
+  std::unique_ptr<cricket::SessionDescription> RestoreMediaSectionsOrder(
+      std::unique_ptr<cricket::SessionDescription> source);
+
+  PatchingParams params_;
+  SignalingContext context_;
+};
+
+}  // namespace webrtc_pc_e2e
+}  // namespace webrtc
+
+#endif  // TEST_PC_E2E_SDP_SDP_CHANGER_H_