message: Fix writing into closed FrameWriter when dumping video in PC framework
  Cr-Commit-Position: refs/heads/master@{#29853}
diff: @@ -1032,15 +1032,15 @@ void PeerConnectionE2EQualityTest::TearDownCall() {
  alice_->pc()->Close();
  bob_->pc()->Close();
  - for (const auto& video_writer : video_writers_) {
  - video_writer->Close();
  - }
  -
  alice_video_sources_.clear();
  bob_video_sources_.clear();
  - video_writers_.clear();
  alice_.reset();
  bob_.reset();
  +
  + for (const auto& video_writer : video_writers_) {
  + video_writer->Close();
  + }
  + video_writers_.clear();
  }
  test::VideoFrameWriter* PeerConnectionE2EQualityTest::MaybeCreateVideoWriter(
  