commit ff84d86d9c57bf154e9329ac29f6cb0448be5e8e
author Markus Handell <handellm@webrtc.org> Tue May 26 16:22:24 2020
committer Commit Bot <commit-bot@chromium.org> Tue May 26 18:10:00 2020
tree 984a4339f72105031b62b3323c50cf03688bd637
parent b7c63ab83ae2b991ff8350bc0aa6427588629287

P2PTransportChannel::OnCandidateResolved: fix resolver leak.

This change fixes a problem where the eventual destruction of a
completed resolver sometimes doesn't happen. This is because the
destruction is posted to the network thread, and if it's destroyed
before the closure is executed, the resolver is leaked.

The fix is in three parts:
1. The resolver->Destroy call is performed on closure destruction
   to make sure it will always run.
2. The closure is executed with task queue. This because the
   RTC_DCHECK on thread:140 fires with the invoker_.
3. It's not possible to guarantee the context Destroy is called on due
   to TaskQueue semantics. Therefore SignalThread::Destroy was changed
   to accept any calling context and only requiring it's the last
   public call to the object.

For unknown reasons, this leak doesn't trigger the leak checker, see
referred bugs for further investigation.

Bug: webrtc:7723, webrtc:11605, chromium:905542
Change-Id: I2681ff1d2416ccbc564974a65ac84781a9ed7aee
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/176125
Commit-Queue: Markus Handell <handellm@webrtc.org>
Reviewed-by: Tommi <tommi@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#31359}