Reland of Make RtcEventLogImpl to use a TaskQueue instead of a helper-thread

webrtc/pc/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 244 matching lines @@
 
   if (!allocator) {
     allocator.reset(new cricket::BasicPortAllocator(
         default_network_manager_.get(), default_socket_factory_.get()));
   }
   network_thread_->Invoke<void>(
       RTC_FROM_HERE, rtc::Bind(&cricket::PortAllocator::SetNetworkIgnoreMask,
                                allocator.get(), options_.network_ignore_mask));
 
   std::unique_ptr<RtcEventLog> event_log =
-      event_log_factory_ ? event_log_factory_->CreateRtcEventLog()
-                         : rtc::MakeUnique<RtcEventLogNullImpl>();
+      worker_thread_->Invoke<std::unique_ptr<RtcEventLog>>(
+          RTC_FROM_HERE,
+          rtc::Bind(&PeerConnectionFactory::CreateRtcEventLog_w, this));
 
   std::unique_ptr<Call> call = worker_thread_->Invoke<std::unique_ptr<Call>>(
       RTC_FROM_HERE,
       rtc::Bind(&PeerConnectionFactory::CreateCall_w, this, event_log.get()));
 
   rtc::scoped_refptr<PeerConnection> pc(
       new rtc::RefCountedObject<PeerConnection>(this, std::move(event_log),
                                                 std::move(call)));
 
   if (!pc->Initialize(configuration, std::move(allocator),
@@ skipping 47 matching lines @@
 }
 
 rtc::Thread* PeerConnectionFactory::worker_thread() {
   return worker_thread_;
 }
 
 rtc::Thread* PeerConnectionFactory::network_thread() {
   return network_thread_;
 }
 
+std::unique_ptr<RtcEventLog> PeerConnectionFactory::CreateRtcEventLog_w() {
+  return event_log_factory_ ? event_log_factory_->CreateRtcEventLog()
+                            : rtc::MakeUnique<RtcEventLogNullImpl>();
+}
+
 std::unique_ptr<Call> PeerConnectionFactory::CreateCall_w(
     RtcEventLog* event_log) {
   const int kMinBandwidthBps = 30000;
   const int kStartBandwidthBps = 300000;
   const int kMaxBandwidthBps = 2000000;
 
   webrtc::Call::Config call_config(event_log);
   if (!channel_manager_->media_engine() || !call_factory_) {
     return nullptr;
   }
   call_config.audio_state = channel_manager_->media_engine()->GetAudioState();
   call_config.bitrate_config.min_bitrate_bps = kMinBandwidthBps;
   call_config.bitrate_config.start_bitrate_bps = kStartBandwidthBps;
   call_config.bitrate_config.max_bitrate_bps = kMaxBandwidthBps;
 
   return std::unique_ptr<Call>(call_factory_->CreateCall(call_config));
 }
 
 }  // namespace webrtc