From 246724b0fe1ff48263039acb776dcba89b990bc0 Mon Sep 17 00:00:00 2001
From: Harald Alvestrand <hta@webrtc.org>
Date: Tue, 3 Dec 2019 22:31:42 +0100
Subject: [PATCH] Move messaging -> PostTask for freeing datachannels

I could find no reason for the extra complexity of doing messaging
in order to schedule a task to be done after the current cycle.
It also simplifies the peerconnection/datachannelcontroller coupling.

Bug: webrtc:11146
Change-Id: I68f45059b9f4a6869fb44b856e05a480f4652365
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/161232
Commit-Queue: Harald Alvestrand <hta@webrtc.org>
Reviewed-by: Steve Anton <steveanton@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#29997}
---
 pc/data_channel_controller.cc | 8 +++++++-
 pc/data_channel_controller.h  | 8 ++------
 pc/peer_connection.cc         | 9 ---------
 pc/peer_connection.h          | 2 --
 4 files changed, 9 insertions(+), 18 deletions(-)

diff --git a/pc/data_channel_controller.cc b/pc/data_channel_controller.cc
index cc9f149364..0eaf44d09f 100644
--- a/pc/data_channel_controller.cc
+++ b/pc/data_channel_controller.cc
@@ -348,7 +348,13 @@ void DataChannelController::OnSctpDataChannelClosed(DataChannel* channel) {
       // we can't free it directly here; we need to free it asynchronously.
       sctp_data_channels_to_free_.push_back(*it);
       sctp_data_channels_.erase(it);
-      pc_->SignalFreeDataChannels();
+      signaling_thread()->PostTask(
+          RTC_FROM_HERE, [self = weak_factory_.GetWeakPtr()] {
+            if (self) {
+              RTC_DCHECK_RUN_ON(self->signaling_thread());
+              self->sctp_data_channels_to_free_.clear();
+            }
+          });
       return;
     }
   }
diff --git a/pc/data_channel_controller.h b/pc/data_channel_controller.h
index bfce16c10c..91bba66066 100644
--- a/pc/data_channel_controller.h
+++ b/pc/data_channel_controller.h
@@ -18,6 +18,7 @@
 
 #include "pc/channel.h"
 #include "pc/data_channel.h"
+#include "rtc_base/weak_ptr.h"
 
 namespace webrtc {
 
@@ -77,12 +78,6 @@ class DataChannelController : public DataChannelProviderInterface,
     return !rtp_data_channels_.empty();
   }
 
-  // Called when it's appropriate to delete released datachannels.
-  void FreeDataChannels() {
-    RTC_DCHECK_RUN_ON(signaling_thread());
-    sctp_data_channels_to_free_.clear();
-  }
-
   void UpdateLocalRtpDataChannels(const cricket::StreamParamsVec& streams);
   void UpdateRemoteRtpDataChannels(const cricket::StreamParamsVec& streams);
 
@@ -207,6 +202,7 @@ class DataChannelController : public DataChannelProviderInterface,
 
   // Owning PeerConnection.
   PeerConnection* const pc_;
+  rtc::WeakPtrFactory<DataChannelController> weak_factory_{this};
 };
 
 }  // namespace webrtc
diff --git a/pc/peer_connection.cc b/pc/peer_connection.cc
index 855df75718..1339638f9f 100644
--- a/pc/peer_connection.cc
+++ b/pc/peer_connection.cc
@@ -136,7 +136,6 @@ enum {
   MSG_SET_SESSIONDESCRIPTION_FAILED,
   MSG_CREATE_SESSIONDESCRIPTION_FAILED,
   MSG_GETSTATS,
-  MSG_FREE_DATACHANNELS,
   MSG_REPORT_USAGE_PATTERN,
 };
 
@@ -4496,10 +4495,6 @@ void PeerConnection::OnMessage(rtc::Message* msg) {
       delete param;
       break;
     }
-    case MSG_FREE_DATACHANNELS: {
-      data_channel_controller_.FreeDataChannels();
-      break;
-    }
     case MSG_REPORT_USAGE_PATTERN: {
       ReportUsagePattern();
       break;
@@ -5676,10 +5671,6 @@ void PeerConnection::OnSctpDataChannelClosed(DataChannel* channel) {
   data_channel_controller_.OnSctpDataChannelClosed(channel);
 }
 
-void PeerConnection::SignalFreeDataChannels() {
-  signaling_thread()->Post(RTC_FROM_HERE, this, MSG_FREE_DATACHANNELS, nullptr);
-}
-
 rtc::scoped_refptr<RtpTransceiverProxyWithInternal<RtpTransceiver>>
 PeerConnection::GetAudioTransceiver() const {
   // This method only works with Plan B SDP, where there is a single
diff --git a/pc/peer_connection.h b/pc/peer_connection.h
index 941b744b13..0e1a1f8ac3 100644
--- a/pc/peer_connection.h
+++ b/pc/peer_connection.h
@@ -317,8 +317,6 @@ class PeerConnection : public PeerConnectionInternal,
   bool GetSctpSslRole(rtc::SSLRole* role);
   // Handler for the "channel closed" signal
   void OnSctpDataChannelClosed(DataChannel* channel);
-  // Sends the MSG_FREE_DATACHANNELS signal
-  void SignalFreeDataChannels();
 
   // Functions made public for testing.
   void ReturnHistogramVeryQuicklyForTesting() {