Revert "Fix bug where we assume new m= sections will always be bundled."

This reverts commit d2b885fd91909f1b17fb11292a8c989d5d883b22.

Reason for revert: Speculative revert for Chromium importer

Original change's description:
> Fix bug where we assume new m= sections will always be bundled.
>
> A recent change [1] assumes that all new m= sections will share the
> first BUNDLE group (if one already exists), which avoids generating
> ICE candidates that are ultimately unnecessary. This is fine for JSEP
> endpoints, but it breaks the following scenarios for non-JSEP endpoints:
>
> * Remote offer adding a new m= section that's not part of any BUNDLE
>   group.
> * Remote offer adding an m= section to the second BUNDLE group.
>
> The latter is specifically problematic for any application that wants
> to bundle all audio streams in one group and all video streams in
> another group when using Unified Plan SDP, to replicate the behavior of
> using Plan B without bundling. It may try to add a video stream only
> for WebRTC to bundle it with audio.
>
> This is fixed by doing some minor re-factoring, having BundleManager
> update the bundle groups at offer time.
>
> Also:
> * Added some additional validation for multiple bundle groups in a
>   subsequent offer, since that now becomes relevant.
> * Improved rollback support, because now rolling back an offer may need
>   to not only remove mid->transport mappings but alter them.
>
> [1]: https://webrtc-review.googlesource.com/c/src/+/221601
>
> Bug: webrtc:12906, webrtc:12999
> Change-Id: I4c6e7020c0be33a782d3608dee88e4e2fceb1be1
> Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/225642
> Reviewed-by: Harald Alvestrand <hta@webrtc.org>
> Reviewed-by: Henrik Boström <hbos@webrtc.org>
> Commit-Queue: Taylor Brandstetter <deadbeef@webrtc.org>
> Cr-Commit-Position: refs/heads/master@{#34544}

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: webrtc:12906, webrtc:12999
Change-Id: I00179d7573f322ad539ff16cad1f85320cfb2270
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/227081
Reviewed-by: Björn Terelius <terelius@google.com>
Reviewed-by: Taylor Brandstetter <deadbeef@webrtc.org>
Commit-Queue: Taylor Brandstetter <deadbeef@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#34578}

pc/jsep_transport_collection.cc

@@ -20,21 +20,8 @@
 
 namespace webrtc {
 
-void BundleManager::Update(const cricket::SessionDescription* description,
+void BundleManager::Update(const cricket::SessionDescription* description) {
-                           SdpType type) {
   RTC_DCHECK_RUN_ON(&sequence_checker_);
-  // Rollbacks should call Rollback, not Update.
-  RTC_DCHECK(type != SdpType::kRollback);
-  bool bundle_groups_changed = false;
-  // TODO(bugs.webrtc.org/3349): Do this for kPrAnswer as well. To make this
-  // work, we also need to make sure PRANSWERs don't call
-  // MaybeDestroyJsepTransport, because the final answer may need the destroyed
-  // transport if it changes the BUNDLE group.
-  if (bundle_policy_ == PeerConnectionInterface::kBundlePolicyMaxBundle ||
-      type == SdpType::kAnswer) {
-    // If our policy is "max-bundle" or this is an answer, update all bundle
-    // groups.
-    bundle_groups_changed = true;
   bundle_groups_.clear();
   for (const cricket::ContentGroup* new_bundle_group :
        description->GetGroupsByName(cricket::GROUP_TYPE_BUNDLE)) {
@@ -43,31 +30,12 @@ void BundleManager::Update(const cricket::SessionDescription* description,
     RTC_DLOG(LS_VERBOSE) << "Establishing bundle group "
                          << new_bundle_group->ToString();
   }
-  } else if (type == SdpType::kOffer) {
+  established_bundle_groups_by_mid_.clear();
-    // If this is an offer, update existing bundle groups.
+  for (const auto& bundle_group : bundle_groups_) {
-    // We do this because as per RFC 8843, section 7.3.2, the answerer cannot
+    for (const std::string& content_name : bundle_group->content_names()) {
-    // remove an m= section from an existing BUNDLE group without rejecting it.
+      established_bundle_groups_by_mid_[content_name] = bundle_group.get();
-    // Thus any m= sections added to a BUNDLE group in this offer can
-    // preemptively start using the bundled transport, as there is no possible
-    // non-bundled fallback.
-    for (const cricket::ContentGroup* new_bundle_group :
-         description->GetGroupsByName(cricket::GROUP_TYPE_BUNDLE)) {
-      // Attempt to find a matching existing group.
-      for (const std::string& mid : new_bundle_group->content_names()) {
-        auto it = established_bundle_groups_by_mid_.find(mid);
-        if (it != established_bundle_groups_by_mid_.end()) {
-          *it->second = *new_bundle_group;
-          bundle_groups_changed = true;
-          RTC_DLOG(LS_VERBOSE)
-              << "Establishing bundle group " << new_bundle_group->ToString();
-          break;
     }
   }
-    }
-  }
-  if (bundle_groups_changed) {
-    RefreshEstablishedBundleGroupsByMid();
-  }
 }
 
 const cricket::ContentGroup* BundleManager::LookupGroupByMid(
@@ -124,34 +92,6 @@ void BundleManager::DeleteGroup(const cricket::ContentGroup* bundle_group) {
   bundle_groups_.erase(bundle_group_it);
 }
 
-void BundleManager::Rollback() {
-  RTC_DCHECK_RUN_ON(&sequence_checker_);
-  bundle_groups_.clear();
-  for (const auto& bundle_group : stable_bundle_groups_) {
-    bundle_groups_.push_back(
-        std::make_unique<cricket::ContentGroup>(*bundle_group));
-  }
-  RefreshEstablishedBundleGroupsByMid();
-}
-
-void BundleManager::Commit() {
-  RTC_DCHECK_RUN_ON(&sequence_checker_);
-  stable_bundle_groups_.clear();
-  for (const auto& bundle_group : bundle_groups_) {
-    stable_bundle_groups_.push_back(
-        std::make_unique<cricket::ContentGroup>(*bundle_group));
-  }
-}
-
-void BundleManager::RefreshEstablishedBundleGroupsByMid() {
-  established_bundle_groups_by_mid_.clear();
-  for (const auto& bundle_group : bundle_groups_) {
-    for (const std::string& content_name : bundle_group->content_names()) {
-      established_bundle_groups_by_mid_[content_name] = bundle_group.get();
-    }
-  }
-}
-
 void JsepTransportCollection::RegisterTransport(
     const std::string& mid,
     std::unique_ptr<cricket::JsepTransport> transport) {
@@ -217,6 +157,8 @@ bool JsepTransportCollection::SetTransportForMid(
   if (it != mid_to_transport_.end() && it->second == jsep_transport)
     return true;
 
+  pending_mids_.push_back(mid);
+
   // The map_change_callback must be called before destroying the
   // transport, because it removes references to the transport
   // in the RTP demuxer.
@@ -249,33 +191,17 @@ void JsepTransportCollection::RemoveTransportForMid(const std::string& mid) {
   RTC_DCHECK(IsConsistent());
 }
 
-bool JsepTransportCollection::RollbackTransports() {
+void JsepTransportCollection::RollbackTransports() {
   RTC_DCHECK_RUN_ON(&sequence_checker_);
-  bool ret = true;
+  for (auto&& mid : pending_mids_) {
-  // First, remove any new mid->transport mappings.
+    RemoveTransportForMid(mid);
-  for (const auto& kv : mid_to_transport_) {
-    if (stable_mid_to_transport_.count(kv.first) == 0) {
-      ret = ret && map_change_callback_(kv.first, nullptr);
   }
-  }
+  pending_mids_.clear();
-  // Next, restore old mappings.
-  for (const auto& kv : stable_mid_to_transport_) {
-    auto it = mid_to_transport_.find(kv.first);
-    if (it == mid_to_transport_.end() || it->second != kv.second) {
-      ret = ret && map_change_callback_(kv.first, kv.second);
-    }
-  }
-  mid_to_transport_ = stable_mid_to_transport_;
-  DestroyUnusedTransports();
-  RTC_DCHECK(IsConsistent());
-  return ret;
 }
 
 void JsepTransportCollection::CommitTransports() {
   RTC_DCHECK_RUN_ON(&sequence_checker_);
-  stable_mid_to_transport_ = mid_to_transport_;
+  pending_mids_.clear();
-  DestroyUnusedTransports();
-  RTC_DCHECK(IsConsistent());
 }
 
 bool JsepTransportCollection::TransportInUse(
@@ -286,11 +212,6 @@ bool JsepTransportCollection::TransportInUse(
       return true;
     }
   }
-  for (const auto& kv : stable_mid_to_transport_) {
-    if (kv.second == jsep_transport) {
-      return true;
-    }
-  }
   return false;
 }
 
@@ -298,7 +219,7 @@ void JsepTransportCollection::MaybeDestroyJsepTransport(
     cricket::JsepTransport* transport) {
   RTC_DCHECK_RUN_ON(&sequence_checker_);
   // Don't destroy the JsepTransport if there are still media sections referring
-  // to it, or if it will be needed in case of rollback.
+  // to it.
   if (TransportInUse(transport)) {
     return;
   }
@@ -312,23 +233,6 @@ void JsepTransportCollection::MaybeDestroyJsepTransport(
   RTC_DCHECK(IsConsistent());
 }
 
-void JsepTransportCollection::DestroyUnusedTransports() {
-  RTC_DCHECK_RUN_ON(&sequence_checker_);
-  bool need_state_change_callback = false;
-  auto it = jsep_transports_by_name_.begin();
-  while (it != jsep_transports_by_name_.end()) {
-    if (TransportInUse(it->second.get())) {
-      ++it;
-    } else {
-      it = jsep_transports_by_name_.erase(it);
-      need_state_change_callback = true;
-    }
-  }
-  if (need_state_change_callback) {
-    state_change_callback_();
-  }
-}
-
 bool JsepTransportCollection::IsConsistent() {
   RTC_DCHECK_RUN_ON(&sequence_checker_);
   for (const auto& it : jsep_transports_by_name_) {
@@ -337,6 +241,13 @@ bool JsepTransportCollection::IsConsistent() {
                         << " is not in use, transport " << it.second.get();
       return false;
     }
+    const auto& lookup = mid_to_transport_.find(it.first);
+    if (lookup->second != it.second.get()) {
+      // Not an error, but unusual.
+      RTC_DLOG(LS_INFO) << "Note: Mid " << it.first << " was registered to "
+                        << it.second.get() << " but currently maps to "
+                        << lookup->second;
+    }
   }
   return true;
 }

pc/jsep_transport_collection.h

@@ -18,7 +18,6 @@
 #include <utility>
 #include <vector>
 
-#include "api/peer_connection_interface.h"
 #include "api/sequence_checker.h"
 #include "pc/jsep_transport.h"
 #include "pc/session_description.h"
@@ -42,8 +41,7 @@ namespace webrtc {
 // 6) Change the logic to do what's right.
 class BundleManager {
  public:
-  explicit BundleManager(PeerConnectionInterface::BundlePolicy bundle_policy)
+  BundleManager() {
-      : bundle_policy_(bundle_policy) {
     // Allow constructor to be called on a different thread.
     sequence_checker_.Detach();
   }
@@ -60,27 +58,17 @@ class BundleManager {
   bool IsFirstMidInGroup(const std::string& mid) const;
   // Update the groups description. This completely replaces the group
   // description with the one from the SessionDescription.
-  void Update(const cricket::SessionDescription* description, SdpType type);
+  void Update(const cricket::SessionDescription* description);
   // Delete a MID from the group that contains it.
   void DeleteMid(const cricket::ContentGroup* bundle_group,
                  const std::string& mid);
   // Delete a group.
   void DeleteGroup(const cricket::ContentGroup* bundle_group);
-  // Roll back to previous stable state.
-  void Rollback();
-  // Commit current bundle groups.
-  void Commit();
 
  private:
-  // Recalculate established_bundle_groups_by_mid_ from bundle_groups_.
-  void RefreshEstablishedBundleGroupsByMid() RTC_RUN_ON(sequence_checker_);
-
   RTC_NO_UNIQUE_ADDRESS SequenceChecker sequence_checker_;
-  PeerConnectionInterface::BundlePolicy bundle_policy_;
   std::vector<std::unique_ptr<cricket::ContentGroup>> bundle_groups_
       RTC_GUARDED_BY(sequence_checker_);
-  std::vector<std::unique_ptr<cricket::ContentGroup>> stable_bundle_groups_
-      RTC_GUARDED_BY(sequence_checker_);
   std::map<std::string, cricket::ContentGroup*>
       established_bundle_groups_by_mid_;
 };
@@ -120,25 +108,17 @@ class JsepTransportCollection {
   // Remove a transport for a MID. This may destroy a transport if it is
   // no longer in use.
   void RemoveTransportForMid(const std::string& mid);
-  // Roll back to previous stable mid-to-transport mappings.
+  // Roll back pending mid-to-transport mappings.
-  bool RollbackTransports();
+  void RollbackTransports();
-  // Commit pending mid-transport mappings (rollback is no longer possible),
+  // Commit pending mid-transport mappings (rollback is no longer possible).
-  // and destroy unused transports because we know now we'll never need them
-  // again.
   void CommitTransports();
-
+  // Returns true if any mid currently maps to this transport.
- private:
-  // Returns true if any mid currently maps to this transport, in either the
-  // pending or stable mapping.
   bool TransportInUse(cricket::JsepTransport* jsep_transport) const;
 
-  // Destroy a transport if it's no longer in use. This includes whether it
+ private:
-  // will be needed in case of rollback.
+  // Destroy a transport if it's no longer in use.
   void MaybeDestroyJsepTransport(cricket::JsepTransport* transport);
 
-  // Destroys all transports that are no longer in use.
-  void DestroyUnusedTransports();
-
   bool IsConsistent();  // For testing only: Verify internal structure.
 
   RTC_NO_UNIQUE_ADDRESS SequenceChecker sequence_checker_;
@@ -150,10 +130,8 @@ class JsepTransportCollection {
   // (BaseChannel/SctpTransport) and the JsepTransport underneath.
   std::map<std::string, cricket::JsepTransport*> mid_to_transport_
       RTC_GUARDED_BY(sequence_checker_);
-  // A snapshot of mid_to_transport_ at the last stable state. Used for
+  // Keep track of mids that have been mapped to transports. Used for rollback.
-  // rollback.
+  std::vector<std::string> pending_mids_ RTC_GUARDED_BY(sequence_checker_);
-  std::map<std::string, cricket::JsepTransport*> stable_mid_to_transport_
-      RTC_GUARDED_BY(sequence_checker_);
   // Callback used to inform subscribers of altered transports.
   const std::function<bool(const std::string& mid,
                            cricket::JsepTransport* transport)>

pc/jsep_transport_controller.cc

@@ -55,8 +55,7 @@ JsepTransportController::JsepTransportController(
             UpdateAggregateStates_n();
           }),
       config_(config),
-      active_reset_srtp_params_(config.active_reset_srtp_params),
+      active_reset_srtp_params_(config.active_reset_srtp_params) {
-      bundles_(config.bundle_policy) {
   // The |transport_observer| is assumed to be non-null.
   RTC_DCHECK(config_.transport_observer);
   RTC_DCHECK(config_.rtcp_handler);
@@ -375,18 +374,13 @@ void JsepTransportController::SetActiveResetSrtpParams(
   }
 }
 
-RTCError JsepTransportController::RollbackTransports() {
+void JsepTransportController::RollbackTransports() {
   if (!network_thread_->IsCurrent()) {
-    return network_thread_->Invoke<RTCError>(
+    network_thread_->Invoke<void>(RTC_FROM_HERE, [=] { RollbackTransports(); });
-        RTC_FROM_HERE, [=] { return RollbackTransports(); });
+    return;
   }
   RTC_DCHECK_RUN_ON(network_thread_);
-  bundles_.Rollback();
+  transports_.RollbackTransports();
-  if (!transports_.RollbackTransports()) {
-    LOG_AND_RETURN_ERROR(RTCErrorType::INTERNAL_ERROR,
-                         "Failed to roll back transport state.");
-  }
-  return RTCError::OK();
 }
 
 rtc::scoped_refptr<webrtc::IceTransportInterface>
@@ -557,6 +551,17 @@ RTCError JsepTransportController::ApplyDescription_n(
         MergeEncryptedHeaderExtensionIdsForBundles(description);
   }
 
+  // Because the creation of transports depends on whether
+  // certain mids are present, we have to process rejection
+  // before we try to create transports.
+  for (size_t i = 0; i < description->contents().size(); ++i) {
+    const cricket::ContentInfo& content_info = description->contents()[i];
+    if (content_info.rejected) {
+      // This may cause groups to be removed from |bundles_.bundle_groups()|.
+      HandleRejectedContent(content_info);
+    }
+  }
+
   for (const cricket::ContentInfo& content_info : description->contents()) {
     // Don't create transports for rejected m-lines and bundled m-lines.
     if (content_info.rejected ||
@@ -577,8 +582,6 @@ RTCError JsepTransportController::ApplyDescription_n(
         description->transport_infos()[i];
 
     if (content_info.rejected) {
-      // This may cause groups to be removed from |bundles_.bundle_groups()|.
-      HandleRejectedContent(content_info);
       continue;
     }
 
@@ -644,7 +647,6 @@ RTCError JsepTransportController::ApplyDescription_n(
   }
   if (type == SdpType::kAnswer) {
     transports_.CommitTransports();
-    bundles_.Commit();
   }
   return RTCError::OK();
 }
@@ -680,44 +682,7 @@ RTCError JsepTransportController::ValidateAndMaybeUpdateBundleGroups(
     }
   }
 
-  if (type == SdpType::kOffer) {
+  if (type == SdpType::kAnswer) {
-    // For an offer, we need to verify that there is not a conflicting mapping
-    // between existing and new bundle groups. For example, if the existing
-    // groups are [[1,2],[3,4]] and new are [[1,3],[2,4]] or [[1,2,3,4]], or
-    // vice versa. Switching things around like this requires a separate offer
-    // that removes the relevant sections from their group, as per RFC 8843,
-    // section 7.5.2.
-    std::map<const cricket::ContentGroup*, const cricket::ContentGroup*>
-        new_bundle_groups_by_existing_bundle_groups;
-    std::map<const cricket::ContentGroup*, const cricket::ContentGroup*>
-        existing_bundle_groups_by_new_bundle_groups;
-    for (const cricket::ContentGroup* new_bundle_group : new_bundle_groups) {
-      for (const std::string& mid : new_bundle_group->content_names()) {
-        cricket::ContentGroup* existing_bundle_group =
-            bundles_.LookupGroupByMid(mid);
-        if (!existing_bundle_group) {
-          continue;
-        }
-        auto it = new_bundle_groups_by_existing_bundle_groups.find(
-            existing_bundle_group);
-        if (it != new_bundle_groups_by_existing_bundle_groups.end() &&
-            it->second != new_bundle_group) {
-          return RTCError(RTCErrorType::INVALID_PARAMETER,
-                          "MID " + mid + " in the offer has changed group.");
-        }
-        new_bundle_groups_by_existing_bundle_groups.insert(
-            std::make_pair(existing_bundle_group, new_bundle_group));
-        it = existing_bundle_groups_by_new_bundle_groups.find(new_bundle_group);
-        if (it != existing_bundle_groups_by_new_bundle_groups.end() &&
-            it->second != existing_bundle_group) {
-          return RTCError(RTCErrorType::INVALID_PARAMETER,
-                          "MID " + mid + " in the offer has changed group.");
-        }
-        existing_bundle_groups_by_new_bundle_groups.insert(
-            std::make_pair(new_bundle_group, existing_bundle_group));
-      }
-    }
-  } else if (type == SdpType::kAnswer) {
     std::vector<const cricket::ContentGroup*> offered_bundle_groups =
         local ? remote_desc_->GetGroupsByName(cricket::GROUP_TYPE_BUNDLE)
               : local_desc_->GetGroupsByName(cricket::GROUP_TYPE_BUNDLE);
@@ -797,7 +762,9 @@ RTCError JsepTransportController::ValidateAndMaybeUpdateBundleGroups(
                     "max-bundle is used but no bundle group found.");
   }
 
-  bundles_.Update(description, type);
+  if (ShouldUpdateBundleGroup(type, description)) {
+    bundles_.Update(description);
+  }
 
   for (const auto& bundle_group : bundles_.bundle_groups()) {
     if (!bundle_group->FirstContentName())
@@ -905,6 +872,26 @@ JsepTransportController::CreateJsepTransportDescription(
       rtp_abs_sendtime_extn_id, transport_info.description);
 }
 
+bool JsepTransportController::ShouldUpdateBundleGroup(
+    SdpType type,
+    const cricket::SessionDescription* description) {
+  if (config_.bundle_policy ==
+      PeerConnectionInterface::kBundlePolicyMaxBundle) {
+    return true;
+  }
+
+  if (type != SdpType::kAnswer) {
+    return false;
+  }
+
+  RTC_DCHECK(local_desc_ && remote_desc_);
+  std::vector<const cricket::ContentGroup*> local_bundles =
+      local_desc_->GetGroupsByName(cricket::GROUP_TYPE_BUNDLE);
+  std::vector<const cricket::ContentGroup*> remote_bundles =
+      remote_desc_->GetGroupsByName(cricket::GROUP_TYPE_BUNDLE);
+  return !local_bundles.empty() && !remote_bundles.empty();
+}
+
 std::vector<int> JsepTransportController::GetEncryptedHeaderExtensionIds(
     const cricket::ContentInfo& content_info) {
   const cricket::MediaContentDescription* content_desc =
@@ -1000,6 +987,21 @@ RTCError JsepTransportController::MaybeCreateJsepTransport(
   if (transport) {
     return RTCError::OK();
   }
+  // If we have agreed to a bundle, the new mid will be added to the bundle
+  // according to JSEP, and the responder can't move it out of the group
+  // according to BUNDLE. So don't create a transport.
+  // The MID will be added to the bundle elsewhere in the code.
+  if (bundles_.bundle_groups().size() > 0) {
+    const auto& default_bundle_group = bundles_.bundle_groups()[0];
+    if (default_bundle_group->content_names().size() > 0) {
+      auto bundle_transport =
+          GetJsepTransportByName(default_bundle_group->content_names()[0]);
+      if (bundle_transport) {
+        transports_.SetTransportForMid(content_info.name, bundle_transport);
+        return RTCError::OK();
+      }
+    }
+  }
   const cricket::MediaContentDescription* content_desc =
       content_info.media_description();
   if (certificate_ && !content_desc->cryptos().empty()) {

pc/jsep_transport_controller.h

@@ -224,7 +224,9 @@ class JsepTransportController : public sigslot::has_slots<> {
 
   void SetActiveResetSrtpParams(bool active_reset_srtp_params);
 
-  RTCError RollbackTransports();
+  // For now the rollback only removes mid to transport mappings
+  // and deletes unused transports, but doesn't consider anything more complex.
+  void RollbackTransports();
 
   // F: void(const std::string&, const std::vector<cricket::Candidate>&)
   template <typename F>
@@ -340,6 +342,9 @@ class JsepTransportController : public sigslot::has_slots<> {
       const std::vector<int>& encrypted_extension_ids,
       int rtp_abs_sendtime_extn_id);
 
+  bool ShouldUpdateBundleGroup(SdpType type,
+                               const cricket::SessionDescription* description);
+
   std::map<const cricket::ContentGroup*, std::vector<int>>
   MergeEncryptedHeaderExtensionIdsForBundles(
       const cricket::SessionDescription* description);

pc/jsep_transport_controller_unittest.cc

@@ -1608,356 +1608,6 @@ TEST_F(JsepTransportControllerTest, MultipleBundleGroupsChangeFirstMid) {
   EXPECT_EQ(mid5_transport, mid6_transport);
 }
 
-TEST_F(JsepTransportControllerTest,
-       MultipleBundleGroupsSectionsAddedInSubsequentOffer) {
-  static const char kMid1Audio[] = "1_audio";
-  static const char kMid2Audio[] = "2_audio";
-  static const char kMid3Audio[] = "3_audio";
-  static const char kMid4Video[] = "4_video";
-  static const char kMid5Video[] = "5_video";
-  static const char kMid6Video[] = "6_video";
-
-  CreateJsepTransportController(JsepTransportController::Config());
-  // Start by grouping (kMid1Audio,kMid2Audio) and (kMid4Video,kMid4f5Video).
-  cricket::ContentGroup bundle_group1(cricket::GROUP_TYPE_BUNDLE);
-  bundle_group1.AddContentName(kMid1Audio);
-  bundle_group1.AddContentName(kMid2Audio);
-  cricket::ContentGroup bundle_group2(cricket::GROUP_TYPE_BUNDLE);
-  bundle_group2.AddContentName(kMid4Video);
-  bundle_group2.AddContentName(kMid5Video);
-
-  auto local_offer = std::make_unique<cricket::SessionDescription>();
-  AddAudioSection(local_offer.get(), kMid1Audio, kIceUfrag1, kIcePwd1,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  AddAudioSection(local_offer.get(), kMid2Audio, kIceUfrag1, kIcePwd1,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  AddVideoSection(local_offer.get(), kMid4Video, kIceUfrag2, kIcePwd2,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  AddVideoSection(local_offer.get(), kMid5Video, kIceUfrag2, kIcePwd2,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  local_offer->AddGroup(bundle_group1);
-  local_offer->AddGroup(bundle_group2);
-
-  auto remote_answer = std::make_unique<cricket::SessionDescription>();
-  AddAudioSection(remote_answer.get(), kMid1Audio, kIceUfrag1, kIcePwd1,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  AddAudioSection(remote_answer.get(), kMid2Audio, kIceUfrag1, kIcePwd1,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  AddVideoSection(remote_answer.get(), kMid4Video, kIceUfrag2, kIcePwd2,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  AddVideoSection(remote_answer.get(), kMid5Video, kIceUfrag2, kIcePwd2,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  remote_answer->AddGroup(bundle_group1);
-  remote_answer->AddGroup(bundle_group2);
-
-  EXPECT_TRUE(transport_controller_
-                  ->SetLocalDescription(SdpType::kOffer, local_offer.get())
-                  .ok());
-  EXPECT_TRUE(transport_controller_
-                  ->SetRemoteDescription(SdpType::kAnswer, remote_answer.get())
-                  .ok());
-
-  // Add kMid3Audio and kMid6Video to the respective audio/video bundle groups.
-  cricket::ContentGroup new_bundle_group1(cricket::GROUP_TYPE_BUNDLE);
-  bundle_group1.AddContentName(kMid3Audio);
-  cricket::ContentGroup new_bundle_group2(cricket::GROUP_TYPE_BUNDLE);
-  bundle_group2.AddContentName(kMid6Video);
-
-  auto subsequent_offer = std::make_unique<cricket::SessionDescription>();
-  AddAudioSection(subsequent_offer.get(), kMid1Audio, kIceUfrag1, kIcePwd1,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  AddAudioSection(subsequent_offer.get(), kMid2Audio, kIceUfrag1, kIcePwd1,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  AddAudioSection(subsequent_offer.get(), kMid3Audio, kIceUfrag1, kIcePwd1,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  AddVideoSection(subsequent_offer.get(), kMid4Video, kIceUfrag2, kIcePwd2,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  AddVideoSection(subsequent_offer.get(), kMid5Video, kIceUfrag2, kIcePwd2,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  AddVideoSection(subsequent_offer.get(), kMid6Video, kIceUfrag2, kIcePwd2,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  subsequent_offer->AddGroup(bundle_group1);
-  subsequent_offer->AddGroup(bundle_group2);
-  EXPECT_TRUE(transport_controller_
-                  ->SetLocalDescription(SdpType::kOffer, subsequent_offer.get())
-                  .ok());
-  auto mid1_transport = transport_controller_->GetRtpTransport(kMid1Audio);
-  auto mid2_transport = transport_controller_->GetRtpTransport(kMid2Audio);
-  auto mid3_transport = transport_controller_->GetRtpTransport(kMid3Audio);
-  auto mid4_transport = transport_controller_->GetRtpTransport(kMid4Video);
-  auto mid5_transport = transport_controller_->GetRtpTransport(kMid5Video);
-  auto mid6_transport = transport_controller_->GetRtpTransport(kMid6Video);
-  EXPECT_NE(mid1_transport, mid4_transport);
-  EXPECT_EQ(mid1_transport, mid2_transport);
-  EXPECT_EQ(mid2_transport, mid3_transport);
-  EXPECT_EQ(mid4_transport, mid5_transport);
-  EXPECT_EQ(mid5_transport, mid6_transport);
-}
-
-TEST_F(JsepTransportControllerTest,
-       MultipleBundleGroupsCombinedInSubsequentOffer) {
-  static const char kMid1Audio[] = "1_audio";
-  static const char kMid2Audio[] = "2_audio";
-  static const char kMid3Video[] = "3_video";
-  static const char kMid4Video[] = "4_video";
-
-  CreateJsepTransportController(JsepTransportController::Config());
-  // Start by grouping (kMid1Audio,kMid2Audio) and (kMid3Video,kMid4Video).
-  cricket::ContentGroup bundle_group1(cricket::GROUP_TYPE_BUNDLE);
-  bundle_group1.AddContentName(kMid1Audio);
-  bundle_group1.AddContentName(kMid2Audio);
-  cricket::ContentGroup bundle_group2(cricket::GROUP_TYPE_BUNDLE);
-  bundle_group2.AddContentName(kMid3Video);
-  bundle_group2.AddContentName(kMid4Video);
-
-  auto local_offer = std::make_unique<cricket::SessionDescription>();
-  AddAudioSection(local_offer.get(), kMid1Audio, kIceUfrag1, kIcePwd1,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  AddAudioSection(local_offer.get(), kMid2Audio, kIceUfrag1, kIcePwd1,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  AddVideoSection(local_offer.get(), kMid3Video, kIceUfrag2, kIcePwd2,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  AddVideoSection(local_offer.get(), kMid4Video, kIceUfrag2, kIcePwd2,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  local_offer->AddGroup(bundle_group1);
-  local_offer->AddGroup(bundle_group2);
-
-  auto remote_answer = std::make_unique<cricket::SessionDescription>();
-  AddAudioSection(remote_answer.get(), kMid1Audio, kIceUfrag1, kIcePwd1,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  AddAudioSection(remote_answer.get(), kMid2Audio, kIceUfrag1, kIcePwd1,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  AddVideoSection(remote_answer.get(), kMid3Video, kIceUfrag2, kIcePwd2,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  AddVideoSection(remote_answer.get(), kMid4Video, kIceUfrag2, kIcePwd2,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  remote_answer->AddGroup(bundle_group1);
-  remote_answer->AddGroup(bundle_group2);
-
-  EXPECT_TRUE(transport_controller_
-                  ->SetLocalDescription(SdpType::kOffer, local_offer.get())
-                  .ok());
-  EXPECT_TRUE(transport_controller_
-                  ->SetRemoteDescription(SdpType::kAnswer, remote_answer.get())
-                  .ok());
-
-  // Switch to grouping (kMid1Audio,kMid2Audio,kMid3Video,kMid4Video).
-  // This is a illegal without first removing m= sections from their groups.
-  cricket::ContentGroup new_bundle_group(cricket::GROUP_TYPE_BUNDLE);
-  new_bundle_group.AddContentName(kMid1Audio);
-  new_bundle_group.AddContentName(kMid2Audio);
-  new_bundle_group.AddContentName(kMid3Video);
-  new_bundle_group.AddContentName(kMid4Video);
-
-  auto subsequent_offer = std::make_unique<cricket::SessionDescription>();
-  AddAudioSection(subsequent_offer.get(), kMid1Audio, kIceUfrag1, kIcePwd1,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  AddAudioSection(subsequent_offer.get(), kMid2Audio, kIceUfrag1, kIcePwd1,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  AddVideoSection(subsequent_offer.get(), kMid3Video, kIceUfrag2, kIcePwd2,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  AddVideoSection(subsequent_offer.get(), kMid4Video, kIceUfrag2, kIcePwd2,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  subsequent_offer->AddGroup(new_bundle_group);
-  EXPECT_FALSE(
-      transport_controller_
-          ->SetLocalDescription(SdpType::kOffer, subsequent_offer.get())
-          .ok());
-}
-
-TEST_F(JsepTransportControllerTest,
-       MultipleBundleGroupsSplitInSubsequentOffer) {
-  static const char kMid1Audio[] = "1_audio";
-  static const char kMid2Audio[] = "2_audio";
-  static const char kMid3Video[] = "3_video";
-  static const char kMid4Video[] = "4_video";
-
-  CreateJsepTransportController(JsepTransportController::Config());
-  // Start by grouping (kMid1Audio,kMid2Audio,kMid3Video,kMid4Video).
-  cricket::ContentGroup bundle_group(cricket::GROUP_TYPE_BUNDLE);
-  bundle_group.AddContentName(kMid1Audio);
-  bundle_group.AddContentName(kMid2Audio);
-  bundle_group.AddContentName(kMid3Video);
-  bundle_group.AddContentName(kMid4Video);
-
-  auto local_offer = std::make_unique<cricket::SessionDescription>();
-  AddAudioSection(local_offer.get(), kMid1Audio, kIceUfrag1, kIcePwd1,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  AddAudioSection(local_offer.get(), kMid2Audio, kIceUfrag1, kIcePwd1,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  AddVideoSection(local_offer.get(), kMid3Video, kIceUfrag2, kIcePwd2,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  AddVideoSection(local_offer.get(), kMid4Video, kIceUfrag2, kIcePwd2,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  local_offer->AddGroup(bundle_group);
-
-  auto remote_answer = std::make_unique<cricket::SessionDescription>();
-  AddAudioSection(remote_answer.get(), kMid1Audio, kIceUfrag1, kIcePwd1,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  AddAudioSection(remote_answer.get(), kMid2Audio, kIceUfrag1, kIcePwd1,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  AddVideoSection(remote_answer.get(), kMid3Video, kIceUfrag2, kIcePwd2,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  AddVideoSection(remote_answer.get(), kMid4Video, kIceUfrag2, kIcePwd2,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  remote_answer->AddGroup(bundle_group);
-
-  EXPECT_TRUE(transport_controller_
-                  ->SetLocalDescription(SdpType::kOffer, local_offer.get())
-                  .ok());
-  EXPECT_TRUE(transport_controller_
-                  ->SetRemoteDescription(SdpType::kAnswer, remote_answer.get())
-                  .ok());
-
-  // Switch to grouping (kMid1Audio,kMid2Audio) and (kMid3Video,kMid4Video).
-  // This is a illegal without first removing m= sections from their groups.
-  cricket::ContentGroup new_bundle_group1(cricket::GROUP_TYPE_BUNDLE);
-  new_bundle_group1.AddContentName(kMid1Audio);
-  new_bundle_group1.AddContentName(kMid2Audio);
-  cricket::ContentGroup new_bundle_group2(cricket::GROUP_TYPE_BUNDLE);
-  new_bundle_group2.AddContentName(kMid3Video);
-  new_bundle_group2.AddContentName(kMid4Video);
-
-  auto subsequent_offer = std::make_unique<cricket::SessionDescription>();
-  AddAudioSection(subsequent_offer.get(), kMid1Audio, kIceUfrag1, kIcePwd1,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  AddAudioSection(subsequent_offer.get(), kMid2Audio, kIceUfrag1, kIcePwd1,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  AddVideoSection(subsequent_offer.get(), kMid3Video, kIceUfrag2, kIcePwd2,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  AddVideoSection(subsequent_offer.get(), kMid4Video, kIceUfrag2, kIcePwd2,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  subsequent_offer->AddGroup(new_bundle_group1);
-  subsequent_offer->AddGroup(new_bundle_group2);
-  EXPECT_FALSE(
-      transport_controller_
-          ->SetLocalDescription(SdpType::kOffer, subsequent_offer.get())
-          .ok());
-}
-
-TEST_F(JsepTransportControllerTest,
-       MultipleBundleGroupsShuffledInSubsequentOffer) {
-  static const char kMid1Audio[] = "1_audio";
-  static const char kMid2Audio[] = "2_audio";
-  static const char kMid3Video[] = "3_video";
-  static const char kMid4Video[] = "4_video";
-
-  CreateJsepTransportController(JsepTransportController::Config());
-  // Start by grouping (kMid1Audio,kMid2Audio) and (kMid3Video,kMid4Video).
-  cricket::ContentGroup bundle_group1(cricket::GROUP_TYPE_BUNDLE);
-  bundle_group1.AddContentName(kMid1Audio);
-  bundle_group1.AddContentName(kMid2Audio);
-  cricket::ContentGroup bundle_group2(cricket::GROUP_TYPE_BUNDLE);
-  bundle_group2.AddContentName(kMid3Video);
-  bundle_group2.AddContentName(kMid4Video);
-
-  auto local_offer = std::make_unique<cricket::SessionDescription>();
-  AddAudioSection(local_offer.get(), kMid1Audio, kIceUfrag1, kIcePwd1,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  AddAudioSection(local_offer.get(), kMid2Audio, kIceUfrag1, kIcePwd1,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  AddVideoSection(local_offer.get(), kMid3Video, kIceUfrag2, kIcePwd2,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  AddVideoSection(local_offer.get(), kMid4Video, kIceUfrag2, kIcePwd2,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  local_offer->AddGroup(bundle_group1);
-  local_offer->AddGroup(bundle_group2);
-
-  auto remote_answer = std::make_unique<cricket::SessionDescription>();
-  AddAudioSection(remote_answer.get(), kMid1Audio, kIceUfrag1, kIcePwd1,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  AddAudioSection(remote_answer.get(), kMid2Audio, kIceUfrag1, kIcePwd1,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  AddVideoSection(remote_answer.get(), kMid3Video, kIceUfrag2, kIcePwd2,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  AddVideoSection(remote_answer.get(), kMid4Video, kIceUfrag2, kIcePwd2,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  remote_answer->AddGroup(bundle_group1);
-  remote_answer->AddGroup(bundle_group2);
-
-  EXPECT_TRUE(transport_controller_
-                  ->SetLocalDescription(SdpType::kOffer, local_offer.get())
-                  .ok());
-  EXPECT_TRUE(transport_controller_
-                  ->SetRemoteDescription(SdpType::kAnswer, remote_answer.get())
-                  .ok());
-
-  // Switch to grouping (kMid1Audio,kMid3Video) and (kMid2Audio,kMid3Video).
-  // This is a illegal without first removing m= sections from their groups.
-  cricket::ContentGroup new_bundle_group1(cricket::GROUP_TYPE_BUNDLE);
-  new_bundle_group1.AddContentName(kMid1Audio);
-  new_bundle_group1.AddContentName(kMid3Video);
-  cricket::ContentGroup new_bundle_group2(cricket::GROUP_TYPE_BUNDLE);
-  new_bundle_group2.AddContentName(kMid2Audio);
-  new_bundle_group2.AddContentName(kMid4Video);
-
-  auto subsequent_offer = std::make_unique<cricket::SessionDescription>();
-  AddAudioSection(subsequent_offer.get(), kMid1Audio, kIceUfrag1, kIcePwd1,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  AddAudioSection(subsequent_offer.get(), kMid2Audio, kIceUfrag1, kIcePwd1,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  AddVideoSection(subsequent_offer.get(), kMid3Video, kIceUfrag2, kIcePwd2,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  AddVideoSection(subsequent_offer.get(), kMid4Video, kIceUfrag2, kIcePwd2,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  subsequent_offer->AddGroup(new_bundle_group1);
-  subsequent_offer->AddGroup(new_bundle_group2);
-  EXPECT_FALSE(
-      transport_controller_
-          ->SetLocalDescription(SdpType::kOffer, subsequent_offer.get())
-          .ok());
-}
-
 // Tests that only a subset of all the m= sections are bundled.
 TEST_F(JsepTransportControllerTest, BundleSubsetOfMediaSections) {
   CreateJsepTransportController(JsepTransportController::Config());
@@ -2409,220 +2059,4 @@ TEST_F(JsepTransportControllerTest, ChangeTaggedMediaSectionMaxBundle) {
           .ok());
 }
 
-TEST_F(JsepTransportControllerTest, RollbackRestoresRejectedTransport) {
-  static const char kMid1Audio[] = "1_audio";
-
-  // Perform initial offer/answer.
-  CreateJsepTransportController(JsepTransportController::Config());
-  auto local_offer = std::make_unique<cricket::SessionDescription>();
-  AddAudioSection(local_offer.get(), kMid1Audio, kIceUfrag1, kIcePwd1,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  std::unique_ptr<cricket::SessionDescription> remote_answer(
-      local_offer->Clone());
-  EXPECT_TRUE(transport_controller_
-                  ->SetLocalDescription(SdpType::kOffer, local_offer.get())
-                  .ok());
-  EXPECT_TRUE(transport_controller_
-                  ->SetRemoteDescription(SdpType::kAnswer, remote_answer.get())
-                  .ok());
-
-  auto mid1_transport = transport_controller_->GetRtpTransport(kMid1Audio);
-
-  // Apply a reoffer which rejects the m= section, causing the transport to be
-  // set to null.
-  auto local_reoffer = std::make_unique<cricket::SessionDescription>();
-  AddAudioSection(local_reoffer.get(), kMid1Audio, kIceUfrag1, kIcePwd1,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  local_reoffer->contents()[0].rejected = true;
-
-  EXPECT_TRUE(transport_controller_
-                  ->SetLocalDescription(SdpType::kOffer, local_reoffer.get())
-                  .ok());
-  auto old_mid1_transport = mid1_transport;
-  mid1_transport = transport_controller_->GetRtpTransport(kMid1Audio);
-  EXPECT_EQ(nullptr, mid1_transport);
-
-  // Rolling back shouldn't just create a new transport for MID 1, it should
-  // restore the old transport.
-  EXPECT_TRUE(transport_controller_->RollbackTransports().ok());
-  mid1_transport = transport_controller_->GetRtpTransport(kMid1Audio);
-  EXPECT_EQ(old_mid1_transport, mid1_transport);
-}
-
-// If an offer with a modified BUNDLE group causes a MID->transport mapping to
-// change, rollback should restore the previous mapping.
-TEST_F(JsepTransportControllerTest, RollbackRestoresPreviousTransportMapping) {
-  static const char kMid1Audio[] = "1_audio";
-  static const char kMid2Audio[] = "2_audio";
-  static const char kMid3Audio[] = "3_audio";
-
-  // Perform an initial offer/answer to establish a (kMid1Audio,kMid2Audio)
-  // group.
-  CreateJsepTransportController(JsepTransportController::Config());
-  cricket::ContentGroup bundle_group(cricket::GROUP_TYPE_BUNDLE);
-  bundle_group.AddContentName(kMid1Audio);
-  bundle_group.AddContentName(kMid2Audio);
-
-  auto local_offer = std::make_unique<cricket::SessionDescription>();
-  AddAudioSection(local_offer.get(), kMid1Audio, kIceUfrag1, kIcePwd1,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  AddVideoSection(local_offer.get(), kMid2Audio, kIceUfrag2, kIcePwd2,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  AddAudioSection(local_offer.get(), kMid3Audio, kIceUfrag3, kIcePwd3,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  local_offer->AddGroup(bundle_group);
-
-  std::unique_ptr<cricket::SessionDescription> remote_answer(
-      local_offer->Clone());
-
-  EXPECT_TRUE(transport_controller_
-                  ->SetLocalDescription(SdpType::kOffer, local_offer.get())
-                  .ok());
-  EXPECT_TRUE(transport_controller_
-                  ->SetRemoteDescription(SdpType::kAnswer, remote_answer.get())
-                  .ok());
-
-  auto mid1_transport = transport_controller_->GetRtpTransport(kMid1Audio);
-  auto mid2_transport = transport_controller_->GetRtpTransport(kMid2Audio);
-  auto mid3_transport = transport_controller_->GetRtpTransport(kMid3Audio);
-  EXPECT_EQ(mid1_transport, mid2_transport);
-  EXPECT_NE(mid1_transport, mid3_transport);
-
-  // Apply a reoffer adding kMid3Audio to the group; transport mapping should
-  // change, even without an answer, since this is an existing group.
-  bundle_group.AddContentName(kMid3Audio);
-  auto local_reoffer = std::make_unique<cricket::SessionDescription>();
-  AddAudioSection(local_reoffer.get(), kMid1Audio, kIceUfrag1, kIcePwd1,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  AddVideoSection(local_reoffer.get(), kMid2Audio, kIceUfrag2, kIcePwd2,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  AddAudioSection(local_reoffer.get(), kMid3Audio, kIceUfrag3, kIcePwd3,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  local_reoffer->AddGroup(bundle_group);
-
-  EXPECT_TRUE(transport_controller_
-                  ->SetLocalDescription(SdpType::kOffer, local_reoffer.get())
-                  .ok());
-
-  // Store the old transport pointer and verify that the offer actually changed
-  // transports.
-  auto old_mid3_transport = mid3_transport;
-  mid1_transport = transport_controller_->GetRtpTransport(kMid1Audio);
-  mid2_transport = transport_controller_->GetRtpTransport(kMid2Audio);
-  mid3_transport = transport_controller_->GetRtpTransport(kMid3Audio);
-  EXPECT_EQ(mid1_transport, mid2_transport);
-  EXPECT_EQ(mid1_transport, mid3_transport);
-
-  // Rolling back shouldn't just create a new transport for MID 3, it should
-  // restore the old transport.
-  EXPECT_TRUE(transport_controller_->RollbackTransports().ok());
-  mid3_transport = transport_controller_->GetRtpTransport(kMid3Audio);
-  EXPECT_EQ(old_mid3_transport, mid3_transport);
-}
-
-// Test that if an offer adds a MID to a specific BUNDLE group and is then
-// rolled back, it can be added to a different BUNDLE group in a new offer.
-// This is effectively testing that rollback resets the BundleManager state.
-TEST_F(JsepTransportControllerTest, RollbackAndAddToDifferentBundleGroup) {
-  static const char kMid1Audio[] = "1_audio";
-  static const char kMid2Audio[] = "2_audio";
-  static const char kMid3Audio[] = "3_audio";
-
-  // Perform an initial offer/answer to establish two bundle groups, each with
-  // one MID.
-  CreateJsepTransportController(JsepTransportController::Config());
-  cricket::ContentGroup bundle_group1(cricket::GROUP_TYPE_BUNDLE);
-  bundle_group1.AddContentName(kMid1Audio);
-  cricket::ContentGroup bundle_group2(cricket::GROUP_TYPE_BUNDLE);
-  bundle_group2.AddContentName(kMid2Audio);
-
-  auto local_offer = std::make_unique<cricket::SessionDescription>();
-  AddAudioSection(local_offer.get(), kMid1Audio, kIceUfrag1, kIcePwd1,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  AddVideoSection(local_offer.get(), kMid2Audio, kIceUfrag2, kIcePwd2,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  local_offer->AddGroup(bundle_group1);
-  local_offer->AddGroup(bundle_group2);
-
-  std::unique_ptr<cricket::SessionDescription> remote_answer(
-      local_offer->Clone());
-
-  EXPECT_TRUE(transport_controller_
-                  ->SetLocalDescription(SdpType::kOffer, local_offer.get())
-                  .ok());
-  EXPECT_TRUE(transport_controller_
-                  ->SetRemoteDescription(SdpType::kAnswer, remote_answer.get())
-                  .ok());
-
-  // Apply an offer that adds kMid3Audio to the first BUNDLE group.,
-  cricket::ContentGroup modified_bundle_group1(cricket::GROUP_TYPE_BUNDLE);
-  modified_bundle_group1.AddContentName(kMid1Audio);
-  modified_bundle_group1.AddContentName(kMid3Audio);
-  auto subsequent_offer_1 = std::make_unique<cricket::SessionDescription>();
-  AddAudioSection(subsequent_offer_1.get(), kMid1Audio, kIceUfrag1, kIcePwd1,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  AddVideoSection(subsequent_offer_1.get(), kMid2Audio, kIceUfrag2, kIcePwd2,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  AddVideoSection(subsequent_offer_1.get(), kMid3Audio, kIceUfrag3, kIcePwd3,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  subsequent_offer_1->AddGroup(modified_bundle_group1);
-  subsequent_offer_1->AddGroup(bundle_group2);
-
-  EXPECT_TRUE(
-      transport_controller_
-          ->SetLocalDescription(SdpType::kOffer, subsequent_offer_1.get())
-          .ok());
-
-  auto mid1_transport = transport_controller_->GetRtpTransport(kMid1Audio);
-  auto mid2_transport = transport_controller_->GetRtpTransport(kMid2Audio);
-  auto mid3_transport = transport_controller_->GetRtpTransport(kMid3Audio);
-  EXPECT_NE(mid1_transport, mid2_transport);
-  EXPECT_EQ(mid1_transport, mid3_transport);
-
-  // Rollback and expect the transport to be reset.
-  EXPECT_TRUE(transport_controller_->RollbackTransports().ok());
-  EXPECT_EQ(nullptr, transport_controller_->GetRtpTransport(kMid3Audio));
-
-  // Apply an offer that adds kMid3Audio to the second BUNDLE group.,
-  cricket::ContentGroup modified_bundle_group2(cricket::GROUP_TYPE_BUNDLE);
-  modified_bundle_group2.AddContentName(kMid2Audio);
-  modified_bundle_group2.AddContentName(kMid3Audio);
-  auto subsequent_offer_2 = std::make_unique<cricket::SessionDescription>();
-  AddAudioSection(subsequent_offer_2.get(), kMid1Audio, kIceUfrag1, kIcePwd1,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  AddVideoSection(subsequent_offer_2.get(), kMid2Audio, kIceUfrag2, kIcePwd2,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  AddVideoSection(subsequent_offer_2.get(), kMid3Audio, kIceUfrag3, kIcePwd3,
-                  cricket::ICEMODE_FULL, cricket::CONNECTIONROLE_ACTPASS,
-                  nullptr);
-  subsequent_offer_2->AddGroup(bundle_group1);
-  subsequent_offer_2->AddGroup(modified_bundle_group2);
-
-  EXPECT_TRUE(
-      transport_controller_
-          ->SetLocalDescription(SdpType::kOffer, subsequent_offer_2.get())
-          .ok());
-
-  mid1_transport = transport_controller_->GetRtpTransport(kMid1Audio);
-  mid2_transport = transport_controller_->GetRtpTransport(kMid2Audio);
-  mid3_transport = transport_controller_->GetRtpTransport(kMid3Audio);
-  EXPECT_NE(mid1_transport, mid2_transport);
-  EXPECT_EQ(mid2_transport, mid3_transport);
-}
-
 }  // namespace webrtc

pc/peer_connection_bundle_unittest.cc

@@ -909,11 +909,11 @@ TEST_F(PeerConnectionBundleTestUnifiedPlan, MultipleBundleGroups) {
 
   EXPECT_TRUE(
       caller->SetLocalDescription(CloneSessionDescription(offer.get())));
-  EXPECT_TRUE(callee->SetRemoteDescription(std::move(offer)));
+  callee->SetRemoteDescription(std::move(offer));
   auto answer = callee->CreateAnswer();
   EXPECT_TRUE(
       callee->SetLocalDescription(CloneSessionDescription(answer.get())));
-  EXPECT_TRUE(caller->SetRemoteDescription(std::move(answer)));
+  caller->SetRemoteDescription(std::move(answer));
 
   // Verify bundling on sender side.
   auto senders = caller->pc()->GetSenders();
@@ -938,59 +938,4 @@ TEST_F(PeerConnectionBundleTestUnifiedPlan, MultipleBundleGroups) {
   EXPECT_NE(receiver0_transport, receiver2_transport);
 }
 
-// Test that, with the "max-compat" bundle policy, it's possible to add an m=
-// section that's not part of an existing bundle group.
-TEST_F(PeerConnectionBundleTestUnifiedPlan, AddNonBundledSection) {
-  RTCConfiguration config;
-  config.bundle_policy = PeerConnectionInterface::kBundlePolicyMaxCompat;
-  auto caller = CreatePeerConnection(config);
-  caller->AddAudioTrack("0_audio");
-  caller->AddAudioTrack("1_audio");
-  auto callee = CreatePeerConnection(config);
-
-  // Establish an existing BUNDLE group.
-  auto offer = caller->CreateOffer(RTCOfferAnswerOptions());
-  EXPECT_TRUE(
-      caller->SetLocalDescription(CloneSessionDescription(offer.get())));
-  EXPECT_TRUE(callee->SetRemoteDescription(std::move(offer)));
-  auto answer = callee->CreateAnswer();
-  EXPECT_TRUE(
-      callee->SetLocalDescription(CloneSessionDescription(answer.get())));
-  EXPECT_TRUE(caller->SetRemoteDescription(std::move(answer)));
-
-  // Add a track but munge SDP so it's not part of the bundle group.
-  caller->AddAudioTrack("3_audio");
-  offer = caller->CreateOffer(RTCOfferAnswerOptions());
-  offer->description()->RemoveGroupByName(cricket::GROUP_TYPE_BUNDLE);
-  cricket::ContentGroup bundle_group(cricket::GROUP_TYPE_BUNDLE);
-  bundle_group.AddContentName("0");
-  bundle_group.AddContentName("1");
-  offer->description()->AddGroup(bundle_group);
-  EXPECT_TRUE(
-      caller->SetLocalDescription(CloneSessionDescription(offer.get())));
-  EXPECT_TRUE(callee->SetRemoteDescription(std::move(offer)));
-  answer = callee->CreateAnswer();
-  EXPECT_TRUE(
-      callee->SetLocalDescription(CloneSessionDescription(answer.get())));
-  EXPECT_TRUE(caller->SetRemoteDescription(std::move(answer)));
-
-  // Verify bundling on the sender side.
-  auto senders = caller->pc()->GetSenders();
-  ASSERT_EQ(senders.size(), 3u);
-  auto sender0_transport = senders[0]->dtls_transport();
-  auto sender1_transport = senders[1]->dtls_transport();
-  auto sender2_transport = senders[2]->dtls_transport();
-  EXPECT_EQ(sender0_transport, sender1_transport);
-  EXPECT_NE(sender0_transport, sender2_transport);
-
-  // Verify bundling on receiver side.
-  auto receivers = callee->pc()->GetReceivers();
-  ASSERT_EQ(receivers.size(), 3u);
-  auto receiver0_transport = receivers[0]->dtls_transport();
-  auto receiver1_transport = receivers[1]->dtls_transport();
-  auto receiver2_transport = receivers[2]->dtls_transport();
-  EXPECT_EQ(receiver0_transport, receiver1_transport);
-  EXPECT_NE(receiver0_transport, receiver2_transport);
-}
-
 }  // namespace webrtc

pc/sdp_offer_answer.cc

@@ -2737,10 +2737,7 @@ RTCError SdpOfferAnswerHandler::Rollback(SdpType desc_type) {
     transceiver->internal()->set_mid(state.mid());
     transceiver->internal()->set_mline_index(state.mline_index());
   }
-  RTCError e = transport_controller()->RollbackTransports();
+  transport_controller()->RollbackTransports();
-  if (!e.ok()) {
-    return e;
-  }
   transceivers()->DiscardStableStates();
   pending_local_description_.reset();
   pending_remote_description_.reset();