Fix the Chrome crash caused by RtcEventLog

webrtc/pc/peerconnection.cc

 /*
  *  Copyright 2012 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 1537 matching lines @@
   return session_->pending_remote_description();
 }
 
 void PeerConnection::Close() {
   TRACE_EVENT0("webrtc", "PeerConnection::Close");
   // Update stats here so that we have the most recent stats for tracks and
   // streams before the channels are closed.
   stats_->UpdateStats(kStatsOutputLevelStandard);
 
   session_->Close();
+  event_log_.reset();
 }
 
 void PeerConnection::OnSessionStateChange(WebRtcSession* /*session*/,
                                           WebRtcSession::State state) {
   switch (state) {
     case WebRtcSession::STATE_INIT:
       ChangeSignalingState(PeerConnectionInterface::kStable);
       break;
     case WebRtcSession::STATE_SENTOFFER:
       ChangeSignalingState(PeerConnectionInterface::kHaveLocalOffer);
@@ skipping 995 matching lines @@
   port_allocator_->set_candidate_filter(
       ConvertIceTransportTypeToCandidateFilter(type));
   // Call this last since it may create pooled allocator sessions using the
   // candidate filter set above.
   return port_allocator_->SetConfiguration(
       stun_servers, turn_servers, candidate_pool_size, prune_turn_ports);
 }
 
 bool PeerConnection::StartRtcEventLog_w(rtc::PlatformFile file,
                                         int64_t max_size_bytes) {
+  if (!event_log_) {
+    return false;
+  }
   return event_log_->StartLogging(file, max_size_bytes);
 }
 
 void PeerConnection::StopRtcEventLog_w() {
-  event_log_->StopLogging();
+  if (event_log_) {
+    event_log_->StopLogging();
+  }
 }
 }  // namespace webrtc