Only use PortAllocator on the network thread.

webrtc/api/peerconnectionfactory.cc

 /*
  *  Copyright 2004 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 269 matching lines @@
     // wrapper object that can be deleted without deleting the underlying
     // |dtls_identity_store_|, protecting it from being deleted multiple times.
     dtls_identity_store.reset(
         new DtlsIdentityStoreWrapper(dtls_identity_store_));
   }
 
   if (!allocator) {
     allocator.reset(new cricket::BasicPortAllocator(
         default_network_manager_.get(), default_socket_factory_.get()));
   }
-  worker_thread_->Invoke<void>(
+  network_thread_->Invoke<void>(
       rtc::Bind(&cricket::PortAllocator::SetNetworkIgnoreMask, allocator.get(),
                 options_.network_ignore_mask));
 
   rtc::scoped_refptr<PeerConnection> pc(
       new rtc::RefCountedObject<PeerConnection>(this));
 
   if (!pc->Initialize(configuration, std::move(allocator),
                       std::move(dtls_identity_store), observer)) {
     return nullptr;
   }
@@ skipping 47 matching lines @@
 }
 
 cricket::MediaEngineInterface* PeerConnectionFactory::CreateMediaEngine_w() {
   ASSERT(worker_thread_ == rtc::Thread::Current());
   return cricket::WebRtcMediaEngineFactory::Create(
       default_adm_.get(), video_encoder_factory_.get(),
       video_decoder_factory_.get());
 }
 
 }  // namespace webrtc