diff --git a/pc/peer_connection.cc b/pc/peer_connection.cc
index e7a1a11..8ac1e83 100644
--- a/pc/peer_connection.cc
+++ b/pc/peer_connection.cc
@@ -698,6 +698,15 @@
   }
 }
 
+const ContentInfo* FindTransceiverMSection(
+    RtpTransceiverProxyWithInternal<RtpTransceiver>* transceiver,
+    const SessionDescriptionInterface* session_description) {
+  return transceiver->mid()
+             ? session_description->description()->GetContentByName(
+                   *transceiver->mid())
+             : nullptr;
+}
+
 }  // namespace
 
 // Upon completion, posts a task to execute the callback of the
@@ -1254,7 +1263,7 @@
   }
 
   stats_->AddStream(local_stream);
-  Observer()->OnRenegotiationNeeded();
+  UpdateNegotiationNeeded();
   return true;
 }
 
@@ -1284,7 +1293,7 @@
   if (IsClosed()) {
     return;
   }
-  Observer()->OnRenegotiationNeeded();
+  UpdateNegotiationNeeded();
 }
 
 RTCErrorOr<rtc::scoped_refptr<RtpSenderInterface>> PeerConnection::AddTrack(
@@ -1313,7 +1322,7 @@
       (IsUnifiedPlan() ? AddTrackUnifiedPlan(track, stream_ids)
                        : AddTrackPlanB(track, stream_ids));
   if (sender_or_error.ok()) {
-    Observer()->OnRenegotiationNeeded();
+    UpdateNegotiationNeeded();
     stats_->AddTrack(track);
   }
   return sender_or_error;
@@ -1460,7 +1469,7 @@
           "Couldn't find sender " + sender->id() + " to remove.");
     }
   }
-  Observer()->OnRenegotiationNeeded();
+  UpdateNegotiationNeeded();
   return RTCError::OK();
 }
 
@@ -1527,7 +1536,7 @@
     cricket::MediaType media_type,
     rtc::scoped_refptr<MediaStreamTrackInterface> track,
     const RtpTransceiverInit& init,
-    bool fire_callback) {
+    bool update_negotiation_needed) {
   RTC_DCHECK((media_type == cricket::MEDIA_TYPE_AUDIO ||
               media_type == cricket::MEDIA_TYPE_VIDEO));
   if (track) {
@@ -1616,8 +1625,8 @@
   auto transceiver = CreateAndAddTransceiver(sender, receiver);
   transceiver->internal()->set_direction(init.direction);
 
-  if (fire_callback) {
-    Observer()->OnRenegotiationNeeded();
+  if (update_negotiation_needed) {
+    UpdateNegotiationNeeded();
   }
 
   return rtc::scoped_refptr<RtpTransceiverInterface>(transceiver);
@@ -1695,7 +1704,7 @@
 void PeerConnection::OnNegotiationNeeded() {
   RTC_DCHECK_RUN_ON(signaling_thread());
   RTC_DCHECK(!IsClosed());
-  Observer()->OnRenegotiationNeeded();
+  UpdateNegotiationNeeded();
 }
 
 rtc::scoped_refptr<RtpSenderInterface> PeerConnection::CreateSender(
@@ -1943,7 +1952,7 @@
   // Trigger the onRenegotiationNeeded event for every new RTP DataChannel, or
   // the first SCTP DataChannel.
   if (data_channel_type() == cricket::DCT_RTP || first_datachannel) {
-    Observer()->OnRenegotiationNeeded();
+    UpdateNegotiationNeeded();
   }
   NoteUsageEvent(UsageEvent::DATA_ADDED);
   return DataChannelProxy::Create(signaling_thread(), channel.get());
@@ -2045,7 +2054,8 @@
         << " transceiver since CreateOffer specified offer_to_receive=1";
     RtpTransceiverInit init;
     init.direction = RtpTransceiverDirection::kRecvOnly;
-    AddTransceiver(media_type, nullptr, init, /*fire_callback=*/false);
+    AddTransceiver(media_type, nullptr, init,
+                   /*update_negotiation_needed=*/false);
   }
 }
 
@@ -2189,6 +2199,16 @@
     // Make UMA notes about what was agreed to.
     ReportNegotiatedSdpSemantics(*local_description());
   }
+
+  if (IsUnifiedPlan()) {
+    bool was_negotiation_needed = is_negotiation_needed_;
+    UpdateNegotiationNeeded();
+    if (signaling_state() == kStable && was_negotiation_needed &&
+        is_negotiation_needed_) {
+      Observer()->OnRenegotiationNeeded();
+    }
+  }
+
   NoteUsageEvent(UsageEvent::SET_LOCAL_DESCRIPTION_CALLED);
 }
 
@@ -2546,6 +2566,15 @@
     ReportNegotiatedSdpSemantics(*remote_description());
   }
 
+  if (IsUnifiedPlan()) {
+    bool was_negotiation_needed = is_negotiation_needed_;
+    UpdateNegotiationNeeded();
+    if (signaling_state() == kStable && was_negotiation_needed &&
+        is_negotiation_needed_) {
+      Observer()->OnRenegotiationNeeded();
+    }
+  }
+
   observer->OnSetRemoteDescriptionComplete(RTCError::OK());
   NoteUsageEvent(UsageEvent::SET_REMOTE_DESCRIPTION_CALLED);
 }
@@ -4158,7 +4187,7 @@
     return;
   }
   AddAudioTrack(track, stream);
-  Observer()->OnRenegotiationNeeded();
+  UpdateNegotiationNeeded();
 }
 
 void PeerConnection::OnAudioTrackRemoved(AudioTrackInterface* track,
@@ -4167,7 +4196,7 @@
     return;
   }
   RemoveAudioTrack(track, stream);
-  Observer()->OnRenegotiationNeeded();
+  UpdateNegotiationNeeded();
 }
 
 void PeerConnection::OnVideoTrackAdded(VideoTrackInterface* track,
@@ -4176,7 +4205,7 @@
     return;
   }
   AddVideoTrack(track, stream);
-  Observer()->OnRenegotiationNeeded();
+  UpdateNegotiationNeeded();
 }
 
 void PeerConnection::OnVideoTrackRemoved(VideoTrackInterface* track,
@@ -4185,7 +4214,7 @@
     return;
   }
   RemoveVideoTrack(track, stream);
-  Observer()->OnRenegotiationNeeded();
+  UpdateNegotiationNeeded();
 }
 
 void PeerConnection::PostSetSessionDescriptionSuccess(
@@ -7125,4 +7154,174 @@
                            nullptr);
 }
 
+void PeerConnection::UpdateNegotiationNeeded() {
+  RTC_DCHECK_RUN_ON(signaling_thread());
+  if (!IsUnifiedPlan()) {
+    Observer()->OnRenegotiationNeeded();
+    return;
+  }
+
+  // If connection's [[IsClosed]] slot is true, abort these steps.
+  if (IsClosed())
+    return;
+
+  // If connection's signaling state is not "stable", abort these steps.
+  if (signaling_state() != kStable)
+    return;
+
+  // NOTE
+  // The negotiation-needed flag will be updated once the state transitions to
+  // "stable", as part of the steps for setting an RTCSessionDescription.
+
+  // If the result of checking if negotiation is needed is false, clear the
+  // negotiation-needed flag by setting connection's [[NegotiationNeeded]] slot
+  // to false, and abort these steps.
+  bool is_negotiation_needed = CheckIfNegotiationIsNeeded();
+  if (!is_negotiation_needed) {
+    is_negotiation_needed_ = false;
+    return;
+  }
+
+  // If connection's [[NegotiationNeeded]] slot is already true, abort these
+  // steps.
+  if (is_negotiation_needed_)
+    return;
+
+  // Set connection's [[NegotiationNeeded]] slot to true.
+  is_negotiation_needed_ = true;
+
+  // Queue a task that runs the following steps:
+  // If connection's [[IsClosed]] slot is true, abort these steps.
+  // If connection's [[NegotiationNeeded]] slot is false, abort these steps.
+  // Fire an event named negotiationneeded at connection.
+  Observer()->OnRenegotiationNeeded();
+}
+
+bool PeerConnection::CheckIfNegotiationIsNeeded() {
+  RTC_DCHECK_RUN_ON(signaling_thread());
+  // 1. If any implementation-specific negotiation is required, as described at
+  // the start of this section, return true.
+
+  // 2. Let description be connection.[[CurrentLocalDescription]].
+  const SessionDescriptionInterface* description = current_local_description();
+  if (!description)
+    return true;
+
+  // 3. If connection has created any RTCDataChannels, and no m= section in
+  // description has been negotiated yet for data, return true.
+  if (!sctp_data_channels_.empty()) {
+    if (!cricket::GetFirstDataContent(description->description()->contents()))
+      return true;
+  }
+
+  // 4. For each transceiver in connection's set of transceivers, perform the
+  // following checks:
+  for (const auto& transceiver : transceivers_) {
+    const ContentInfo* current_local_msection =
+        FindTransceiverMSection(transceiver.get(), description);
+
+    const ContentInfo* current_remote_msection = FindTransceiverMSection(
+        transceiver.get(), current_remote_description());
+
+    // 4.3 If transceiver is stopped and is associated with an m= section,
+    // but the associated m= section is not yet rejected in
+    // connection.[[CurrentLocalDescription]] or
+    // connection.[[CurrentRemoteDescription]], return true.
+    if (transceiver->stopped()) {
+      if (current_local_msection && !current_local_msection->rejected &&
+          ((current_remote_msection && !current_remote_msection->rejected) ||
+           !current_remote_msection)) {
+        return true;
+      }
+      continue;
+    }
+
+    // 4.1 If transceiver isn't stopped and isn't yet associated with an m=
+    // section in description, return true.
+    if (!current_local_msection)
+      return true;
+
+    const MediaContentDescription* current_local_media_description =
+        current_local_msection->media_description();
+    // 4.2 If transceiver isn't stopped and is associated with an m= section
+    // in description then perform the following checks:
+
+    // 4.2.1 If transceiver.[[Direction]] is "sendrecv" or "sendonly", and the
+    // associated m= section in description either doesn't contain a single
+    // "a=msid" line, or the number of MSIDs from the "a=msid" lines in this
+    // m= section, or the MSID values themselves, differ from what is in
+    // transceiver.sender.[[AssociatedMediaStreamIds]], return true.
+    if (RtpTransceiverDirectionHasSend(transceiver->direction())) {
+      if (current_local_media_description->streams().size() == 0)
+        return true;
+
+      std::vector<std::string> msection_msids;
+      for (const auto& stream : current_local_media_description->streams()) {
+        for (const std::string& msid : stream.stream_ids())
+          msection_msids.push_back(msid);
+      }
+
+      std::vector<std::string> transceiver_msids =
+          transceiver->sender()->stream_ids();
+      if (msection_msids.size() != transceiver_msids.size())
+        return true;
+
+      absl::c_sort(transceiver_msids);
+      absl::c_sort(msection_msids);
+      if (transceiver_msids != msection_msids)
+        return true;
+    }
+
+    // 4.2.2 If description is of type "offer", and the direction of the
+    // associated m= section in neither connection.[[CurrentLocalDescription]]
+    // nor connection.[[CurrentRemoteDescription]] matches
+    // transceiver.[[Direction]], return true.
+    if (description->GetType() == SdpType::kOffer) {
+      if (!current_remote_description())
+        return true;
+
+      if (!current_remote_msection)
+        return true;
+
+      RtpTransceiverDirection current_local_direction =
+          current_local_media_description->direction();
+      RtpTransceiverDirection current_remote_direction =
+          current_remote_msection->media_description()->direction();
+      if (transceiver->direction() != current_local_direction &&
+          transceiver->direction() !=
+              RtpTransceiverDirectionReversed(current_remote_direction)) {
+        return true;
+      }
+    }
+
+    // 4.2.3 If description is of type "answer", and the direction of the
+    // associated m= section in the description does not match
+    // transceiver.[[Direction]] intersected with the offered direction (as
+    // described in [JSEP] (section 5.3.1.)), return true.
+    if (description->GetType() == SdpType::kAnswer) {
+      if (!remote_description())
+        return true;
+
+      const ContentInfo* offered_remote_msection =
+          FindTransceiverMSection(transceiver.get(), remote_description());
+
+      RtpTransceiverDirection offered_direction =
+          offered_remote_msection
+              ? offered_remote_msection->media_description()->direction()
+              : RtpTransceiverDirection::kInactive;
+
+      if (current_local_media_description->direction() !=
+          (RtpTransceiverDirectionIntersection(
+              transceiver->direction(),
+              RtpTransceiverDirectionReversed(offered_direction)))) {
+        return true;
+      }
+    }
+  }
+
+  // If all the preceding checks were performed and true was not returned,
+  // nothing remains to be negotiated; return false.
+  return false;
+}
+
 }  // namespace webrtc
diff --git a/pc/peer_connection.h b/pc/peer_connection.h
index c639a58..2cf3662 100644
--- a/pc/peer_connection.h
+++ b/pc/peer_connection.h
@@ -1086,6 +1086,9 @@
     return media_transport;
   }
 
+  void UpdateNegotiationNeeded();
+  bool CheckIfNegotiationIsNeeded();
+
   sigslot::signal1<DataChannel*> SignalDataChannelCreated_
       RTC_GUARDED_BY(signaling_thread());
 
@@ -1329,6 +1332,7 @@
   // channel manager and the session description factory.
   rtc::UniqueRandomIdGenerator ssrc_generator_
       RTC_GUARDED_BY(signaling_thread());
+  bool is_negotiation_needed_ RTC_GUARDED_BY(signaling_thread()) = false;
 };
 
 }  // namespace webrtc
diff --git a/pc/peer_connection_interface_unittest.cc b/pc/peer_connection_interface_unittest.cc
index e69fc96..d73e45a 100644
--- a/pc/peer_connection_interface_unittest.cc
+++ b/pc/peer_connection_interface_unittest.cc
@@ -814,8 +814,6 @@
     auto sender_or_error =
         pc_->AddTrack(CreateVideoTrack(track_label), stream_ids);
     ASSERT_EQ(RTCErrorType::NONE, sender_or_error.error().type());
-    EXPECT_TRUE_WAIT(observer_.renegotiation_needed_, kTimeout);
-    observer_.renegotiation_needed_ = false;
   }
 
   void AddVideoStream(const std::string& label) {
@@ -823,8 +821,6 @@
         pc_factory_->CreateLocalMediaStream(label));
     stream->AddTrack(CreateVideoTrack(label + "v0"));
     ASSERT_TRUE(pc_->AddStream(stream));
-    EXPECT_TRUE_WAIT(observer_.renegotiation_needed_, kTimeout);
-    observer_.renegotiation_needed_ = false;
   }
 
   rtc::scoped_refptr<AudioTrackInterface> CreateAudioTrack(
@@ -837,8 +833,6 @@
     auto sender_or_error =
         pc_->AddTrack(CreateAudioTrack(track_label), stream_ids);
     ASSERT_EQ(RTCErrorType::NONE, sender_or_error.error().type());
-    EXPECT_TRUE_WAIT(observer_.renegotiation_needed_, kTimeout);
-    observer_.renegotiation_needed_ = false;
   }
 
   void AddAudioStream(const std::string& label) {
@@ -846,8 +840,6 @@
         pc_factory_->CreateLocalMediaStream(label));
     stream->AddTrack(CreateAudioTrack(label + "a0"));
     ASSERT_TRUE(pc_->AddStream(stream));
-    EXPECT_TRUE_WAIT(observer_.renegotiation_needed_, kTimeout);
-    observer_.renegotiation_needed_ = false;
   }
 
   void AddAudioVideoStream(const std::string& stream_id,
@@ -859,8 +851,6 @@
     stream->AddTrack(CreateAudioTrack(audio_track_label));
     stream->AddTrack(CreateVideoTrack(video_track_label));
     ASSERT_TRUE(pc_->AddStream(stream));
-    EXPECT_TRUE_WAIT(observer_.renegotiation_needed_, kTimeout);
-    observer_.renegotiation_needed_ = false;
   }
 
   rtc::scoped_refptr<RtpReceiverInterface> GetFirstReceiverOfType(
@@ -2204,9 +2194,12 @@
   EXPECT_TRUE(observer_.renegotiation_needed_);
   observer_.renegotiation_needed_ = false;
 
+  CreateOfferReceiveAnswer();
+
   rtc::scoped_refptr<DataChannelInterface> dc2 =
       pc_->CreateDataChannel("test2", NULL);
-  EXPECT_TRUE(observer_.renegotiation_needed_);
+  EXPECT_EQ(observer_.renegotiation_needed_,
+            GetParam() == SdpSemantics::kPlanB);
 }
 
 // This test that a data channel closes when a PeerConnection is deleted/closed.
@@ -3894,14 +3887,17 @@
   EXPECT_TRUE_WAIT(observer_.renegotiation_needed_, kTimeout);
   observer_.renegotiation_needed_ = false;
 
+  CreateOfferReceiveAnswer();
   stream->AddTrack(video_track);
   EXPECT_TRUE_WAIT(observer_.renegotiation_needed_, kTimeout);
   observer_.renegotiation_needed_ = false;
 
+  CreateOfferReceiveAnswer();
   stream->RemoveTrack(audio_track);
   EXPECT_TRUE_WAIT(observer_.renegotiation_needed_, kTimeout);
   observer_.renegotiation_needed_ = false;
 
+  CreateOfferReceiveAnswer();
   stream->RemoveTrack(video_track);
   EXPECT_TRUE_WAIT(observer_.renegotiation_needed_, kTimeout);
   observer_.renegotiation_needed_ = false;
diff --git a/pc/peer_connection_rtp_unittest.cc b/pc/peer_connection_rtp_unittest.cc
index c03bab4..6925300 100644
--- a/pc/peer_connection_rtp_unittest.cc
+++ b/pc/peer_connection_rtp_unittest.cc
@@ -1135,11 +1135,14 @@
 TEST_F(PeerConnectionRtpTestUnifiedPlan,
        AddTrackChangesDirectionFromInactiveToSendOnly) {
   auto caller = CreatePeerConnection();
+  auto callee = CreatePeerConnection();
 
   RtpTransceiverInit init;
   init.direction = RtpTransceiverDirection::kInactive;
   auto transceiver = caller->AddTransceiver(cricket::MEDIA_TYPE_AUDIO, init);
+  EXPECT_TRUE(caller->observer()->negotiation_needed());
 
+  ASSERT_TRUE(caller->ExchangeOfferAnswerWith(callee.get()));
   caller->observer()->clear_negotiation_needed();
   ASSERT_TRUE(caller->AddAudioTrack("a"));
   EXPECT_TRUE(caller->observer()->negotiation_needed());
@@ -1152,11 +1155,14 @@
 TEST_F(PeerConnectionRtpTestUnifiedPlan,
        AddTrackChangesDirectionFromRecvOnlyToSendRecv) {
   auto caller = CreatePeerConnection();
+  auto callee = CreatePeerConnection();
 
   RtpTransceiverInit init;
   init.direction = RtpTransceiverDirection::kRecvOnly;
   auto transceiver = caller->AddTransceiver(cricket::MEDIA_TYPE_AUDIO, init);
+  EXPECT_TRUE(caller->observer()->negotiation_needed());
 
+  ASSERT_TRUE(caller->ExchangeOfferAnswerWith(callee.get()));
   caller->observer()->clear_negotiation_needed();
   ASSERT_TRUE(caller->AddAudioTrack("a"));
   EXPECT_TRUE(caller->observer()->negotiation_needed());
@@ -1219,18 +1225,21 @@
 TEST_F(PeerConnectionRtpTestUnifiedPlan,
        RemoveTrackChangesDirectionFromSendRecvToRecvOnly) {
   auto caller = CreatePeerConnection();
+  auto callee = CreatePeerConnection();
 
   RtpTransceiverInit init;
   init.direction = RtpTransceiverDirection::kSendRecv;
   auto transceiver =
       caller->AddTransceiver(caller->CreateAudioTrack("a"), init);
+  EXPECT_TRUE(caller->observer()->negotiation_needed());
 
+  ASSERT_TRUE(caller->ExchangeOfferAnswerWith(callee.get()));
   caller->observer()->clear_negotiation_needed();
+
   ASSERT_TRUE(caller->pc()->RemoveTrack(transceiver->sender()));
   EXPECT_TRUE(caller->observer()->negotiation_needed());
 
   EXPECT_EQ(RtpTransceiverDirection::kRecvOnly, transceiver->direction());
-  EXPECT_TRUE(caller->observer()->renegotiation_needed_);
 }
 
 // Test that calling RemoveTrack on a sender where the transceiver is configured
@@ -1238,13 +1247,17 @@
 TEST_F(PeerConnectionRtpTestUnifiedPlan,
        RemoveTrackChangesDirectionFromSendOnlyToInactive) {
   auto caller = CreatePeerConnection();
+  auto callee = CreatePeerConnection();
 
   RtpTransceiverInit init;
   init.direction = RtpTransceiverDirection::kSendOnly;
   auto transceiver =
       caller->AddTransceiver(caller->CreateAudioTrack("a"), init);
+  EXPECT_TRUE(caller->observer()->negotiation_needed());
 
+  ASSERT_TRUE(caller->ExchangeOfferAnswerWith(callee.get()));
   caller->observer()->clear_negotiation_needed();
+
   ASSERT_TRUE(caller->pc()->RemoveTrack(transceiver->sender()));
   EXPECT_TRUE(caller->observer()->negotiation_needed());
 
@@ -1394,10 +1407,15 @@
 TEST_F(PeerConnectionRtpTestUnifiedPlan,
        RenegotiationNeededAfterTransceiverSetDirection) {
   auto caller = CreatePeerConnection();
+  auto callee = CreatePeerConnection();
+  EXPECT_FALSE(caller->observer()->negotiation_needed());
 
   auto transceiver = caller->AddTransceiver(cricket::MEDIA_TYPE_AUDIO);
+  EXPECT_TRUE(caller->observer()->negotiation_needed());
 
+  ASSERT_TRUE(caller->ExchangeOfferAnswerWith(callee.get()));
   caller->observer()->clear_negotiation_needed();
+
   transceiver->SetDirection(RtpTransceiverDirection::kInactive);
   EXPECT_TRUE(caller->observer()->negotiation_needed());
 }
@@ -1777,6 +1795,42 @@
   }
 }
 
+// This test exercises the code path that fires a NegotiationNeeded
+// notification when the stream IDs of the local description differ from
+// the ones in the transceiver. Since SetStreams() is not yet available
+// on RtpSenderInterface, adding a track is used to trigger the check for
+// the NegotiationNeeded notification.
+// TODO(https://crbug.com/webrtc/10129): Replace this test with a test that
+// checks that calling SetStreams() on a sender fires the notification once
+// the method becomes available in RtpSenderInterface.
+TEST_F(PeerConnectionRtpTestUnifiedPlan,
+       ChangeAssociatedStreamsTriggersRenegotiation) {
+  auto caller = CreatePeerConnection();
+  auto callee = CreatePeerConnection();
+
+  RtpTransceiverInit init;
+  init.direction = RtpTransceiverDirection::kSendRecv;
+  auto transceiver =
+      caller->AddTransceiver(caller->CreateAudioTrack("a"), init);
+  EXPECT_TRUE(caller->observer()->negotiation_needed());
+
+  ASSERT_TRUE(caller->ExchangeOfferAnswerWith(callee.get()));
+  caller->observer()->clear_negotiation_needed();
+
+  SessionDescriptionInterface* cld = const_cast<SessionDescriptionInterface*>(
+      caller->pc()->current_local_description());
+  ASSERT_EQ(cld->description()->contents().size(), 1u);
+
+  cricket::SessionDescription* description = cld->description();
+  cricket::ContentInfo& content_info = description->contents()[0];
+  ASSERT_EQ(content_info.media_description()->mutable_streams().size(), 1u);
+  content_info.media_description()->mutable_streams()[0].set_stream_ids(
+      {"stream3", "stream4", "stream5"});
+
+  ASSERT_TRUE(caller->AddTrack(caller->CreateAudioTrack("a2")));
+  EXPECT_TRUE(caller->observer()->negotiation_needed());
+}
+
 INSTANTIATE_TEST_SUITE_P(PeerConnectionRtpTest,
                          PeerConnectionRtpTest,
                          Values(SdpSemantics::kPlanB,
diff --git a/pc/rtp_media_utils.cc b/pc/rtp_media_utils.cc
index f4a6120..6e8be58 100644
--- a/pc/rtp_media_utils.cc
+++ b/pc/rtp_media_utils.cc
@@ -81,4 +81,14 @@
   return "";
 }
 
+RtpTransceiverDirection RtpTransceiverDirectionIntersection(
+    RtpTransceiverDirection lhs,
+    RtpTransceiverDirection rhs) {
+  return RtpTransceiverDirectionFromSendRecv(
+      RtpTransceiverDirectionHasSend(lhs) &&
+          RtpTransceiverDirectionHasSend(rhs),
+      RtpTransceiverDirectionHasRecv(lhs) &&
+          RtpTransceiverDirectionHasRecv(rhs));
+}
+
 }  // namespace webrtc
diff --git a/pc/rtp_media_utils.h b/pc/rtp_media_utils.h
index 3ff40c9..f556fe3 100644
--- a/pc/rtp_media_utils.h
+++ b/pc/rtp_media_utils.h
@@ -44,6 +44,11 @@
 // Returns an unspecified string representation of the given direction.
 const char* RtpTransceiverDirectionToString(RtpTransceiverDirection direction);
 
+// Returns the intersection of the directions of two transceivers.
+RtpTransceiverDirection RtpTransceiverDirectionIntersection(
+    RtpTransceiverDirection lhs,
+    RtpTransceiverDirection rhs);
+
 #ifdef UNIT_TEST
 inline std::ostream& operator<<(  // no-presubmit-check TODO(webrtc:8982)
     std::ostream& os,             // no-presubmit-check TODO(webrtc:8982)