Handle any number of role conflicts; not just the first.

webrtc/p2p/base/transportcontroller.cc

 /*
  *  Copyright 2015 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.
  */
 
@@ skipping 558 matching lines @@
 
 void TransportController::OnChannelCandidatesRemoved(
     const Candidates& candidates) {
   RTC_DCHECK(signaling_thread_->IsCurrent());
   SignalCandidatesRemoved(candidates);
 }
 
 void TransportController::OnChannelRoleConflict_n(
     TransportChannelImpl* channel) {
   RTC_DCHECK(network_thread_->IsCurrent());
-
-  if (ice_role_switch_) {
-    LOG(LS_WARNING)
-        << "Repeat of role conflict signal from TransportChannelImpl.";
-    return;
-  }
-
-  ice_role_switch_ = true;
+  // Note: since the role conflict is handled entirely on the network thread,
+  // we don't need to worry about role conflicts occurring on two ports at once.
+  // The first one encountered should immediately reverse the role.
   IceRole reversed_role = (ice_role_ == ICEROLE_CONTROLLING)
                               ? ICEROLE_CONTROLLED
                               : ICEROLE_CONTROLLING;
-  for (const auto& kv : transports_) {
-    kv.second->SetIceRole(reversed_role);
-  }
+  LOG(LS_INFO) << "Got role conflict; switching to "
+               << (reversed_role == ICEROLE_CONTROLLING ? "controlling"
+                                                        : "controlled")
+               << " role.";
+  SetIceRole_n(reversed_role);
 }
 
 void TransportController::OnChannelConnectionRemoved_n(
     TransportChannelImpl* channel) {
   RTC_DCHECK(network_thread_->IsCurrent());
   LOG(LS_INFO) << channel->transport_name() << " TransportChannel "
                << channel->component()
                << " connection removed. Check if state is complete.";
   UpdateAggregateStates_n();
 }
@@ skipping 52 matching lines @@
   }
   if (gathering_state_ != new_gathering_state) {
     gathering_state_ = new_gathering_state;
     signaling_thread_->Post(
         this, MSG_ICEGATHERINGSTATE,
         new rtc::TypedMessageData<IceGatheringState>(new_gathering_state));
   }
 }
 
 }  // namespace cricket