Revert "Moves TransportFeedbackAdapter to TaskQueue."

This reverts commit 62d01cde6f6ec1fa91b1e5234a7922ad1a4ce036.

Reason for revert: Causes SIGSEGV in webrtc::RTPSender::BuildRtxPacket.

Original change's description:
> Moves TransportFeedbackAdapter to TaskQueue.
>
> Bug: webrtc:9883
> Change-Id: Id87e281751d98043f4470df5a71d458f4cd654c1
> Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/158793
> Commit-Queue: Sebastian Jansson <srte@webrtc.org>
> Reviewed-by: Erik Språng <sprang@webrtc.org>
> Cr-Commit-Position: refs/heads/master@{#30037}

TBR=sprang@webrtc.org,srte@webrtc.org

# Not skipping CQ checks because original CL landed > 1 day ago.

No-Try: True
Bug: webrtc:9883
Change-Id: If54bdb8694144fae3fafbabd72d1ac1198e51aa6
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/161726
Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org>
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#30052}
diff --git a/call/rtp_video_sender_unittest.cc b/call/rtp_video_sender_unittest.cc
index 94d0931..8190eea 100644
--- a/call/rtp_video_sender_unittest.cc
+++ b/call/rtp_video_sender_unittest.cc
@@ -135,24 +135,17 @@
                      VideoEncoderConfig::ContentType::kRealtimeVideo),
         retransmission_rate_limiter_(time_controller_.GetClock(),
                                      kRetransmitWindowSizeMs) {
-    rtc::Event done;
-    transport_controller_.GetWorkerQueue()->PostTask([&]() {
-      std::map<uint32_t, RtpState> suspended_ssrcs;
-
-      router_ = std::make_unique<RtpVideoSender>(
-          time_controller_.GetClock(), suspended_ssrcs,
-          suspended_payload_states, config_.rtp,
-          config_.rtcp_report_interval_ms, &transport_,
-          CreateObservers(&call_stats_, &encoder_feedback_, &stats_proxy_,
-                          &stats_proxy_, &stats_proxy_, &stats_proxy_,
-                          frame_count_observer, &stats_proxy_, &stats_proxy_,
-                          &send_delay_stats_),
-          &transport_controller_, &event_log_, &retransmission_rate_limiter_,
-          std::make_unique<FecControllerDefault>(time_controller_.GetClock()),
-          nullptr, CryptoOptions{});
-      done.Set();
-    });
-    done.Wait(rtc::Event::kForever);
+    std::map<uint32_t, RtpState> suspended_ssrcs;
+    router_ = std::make_unique<RtpVideoSender>(
+        time_controller_.GetClock(), suspended_ssrcs, suspended_payload_states,
+        config_.rtp, config_.rtcp_report_interval_ms, &transport_,
+        CreateObservers(&call_stats_, &encoder_feedback_, &stats_proxy_,
+                        &stats_proxy_, &stats_proxy_, &stats_proxy_,
+                        frame_count_observer, &stats_proxy_, &stats_proxy_,
+                        &send_delay_stats_),
+        &transport_controller_, &event_log_, &retransmission_rate_limiter_,
+        std::make_unique<FecControllerDefault>(time_controller_.GetClock()),
+        nullptr, CryptoOptions{});
   }
   RtpVideoSenderTestFixture(
       const std::vector<uint32_t>& ssrcs,
@@ -164,14 +157,7 @@
                                   payload_type,
                                   suspended_payload_states,
                                   /*frame_count_observer=*/nullptr) {}
-  ~RtpVideoSenderTestFixture() {
-    rtc::Event done;
-    transport_controller_.GetWorkerQueue()->PostTask([&]() {
-      router_.reset();
-      done.Set();
-    });
-    done.Wait(rtc::Event::kForever);
-  }
+
   RtpVideoSender* router() { return router_.get(); }
   MockTransport& transport() { return transport_; }
   void AdvanceTime(TimeDelta delta) { time_controller_.AdvanceTime(delta); }