Revert of Fix race / crash in OnNetworkRouteChanged(). (patchset #5 id:80001 of https://codereview.webrtc.org/2366333003/ )

Reason for revert:
Caused issues with webrtc_perf_tests on build bots.

Original issue's description:
> Fix race / crash in OnNetworkRouteChanged().
>
> To achieve this some refactoring was done to make it possible to synchronize
> access to the DelayBasedBwe in TransportFeedbackAdapter:
> - The callback was removed from DelayBasedBwe, it now instead returns its
>   result.
> - TransportFeedbackAdapter was moved to modules/congestion_controller to avoid
>   unnecessary dependencies.
>
> Reenables previously disabled flaky test. Can no longer reproduce flakiness with gtest-parallel and asan/tsan builds.
>
> BUG=webrtc:6427, webrtc:6422
>
> Committed: https://crrev.com/fd0d42669204e6dd92a60736bca7ae0196663024
> Cr-Commit-Position: refs/heads/master@{#14430}

TBR=terelius@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=webrtc:6427, webrtc:6422

Review-Url: https://codereview.webrtc.org/2377303002
Cr-Commit-Position: refs/heads/master@{#14433}
diff --git a/webrtc/modules/bitrate_controller/bitrate_controller_impl.cc b/webrtc/modules/bitrate_controller/bitrate_controller_impl.cc
index b336367..bc2f1f6 100644
--- a/webrtc/modules/bitrate_controller/bitrate_controller_impl.cc
+++ b/webrtc/modules/bitrate_controller/bitrate_controller_impl.cc
@@ -186,18 +186,22 @@
   MaybeTriggerOnNetworkChanged();
 }
 
-void BitrateControllerImpl::OnDelayBasedBweResult(
-    const DelayBasedBwe::Result& result) {
-  if (!result.updated)
-    return;
+void BitrateControllerImpl::OnProbeBitrate(uint32_t bitrate_bps) {
   {
     rtc::CritScope cs(&critsect_);
-    if (result.probe) {
-      bandwidth_estimation_.SetSendBitrate(result.target_bitrate_bps);
-    } else {
-      bandwidth_estimation_.UpdateDelayBasedEstimate(
-          clock_->TimeInMilliseconds(), result.target_bitrate_bps);
-    }
+    bandwidth_estimation_.SetSendBitrate(bitrate_bps);
+  }
+  MaybeTriggerOnNetworkChanged();
+}
+
+// TODO(isheriff): Perhaps need new interface for invocation from DelayBasedBwe.
+void BitrateControllerImpl::OnReceiveBitrateChanged(
+    const std::vector<uint32_t>& ssrcs,
+    uint32_t bitrate_bps) {
+  {
+    rtc::CritScope cs(&critsect_);
+    bandwidth_estimation_.UpdateDelayBasedEstimate(clock_->TimeInMilliseconds(),
+                                                   bitrate_bps);
   }
   MaybeTriggerOnNetworkChanged();
 }