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/include/bitrate_controller.h b/webrtc/modules/bitrate_controller/include/bitrate_controller.h
index 7400d7d..90b6471 100644
--- a/webrtc/modules/bitrate_controller/include/bitrate_controller.h
+++ b/webrtc/modules/bitrate_controller/include/bitrate_controller.h
@@ -17,9 +17,9 @@
 
 #include <map>
 
-#include "webrtc/modules/congestion_controller/delay_based_bwe.h"
 #include "webrtc/modules/include/module.h"
 #include "webrtc/modules/pacing/paced_sender.h"
+#include "webrtc/modules/remote_bitrate_estimator/include/remote_bitrate_estimator.h"
 #include "webrtc/modules/rtp_rtcp/include/rtp_rtcp_defines.h"
 
 namespace webrtc {
@@ -44,7 +44,7 @@
   virtual ~BitrateObserver() {}
 };
 
-class BitrateController : public Module {
+class BitrateController : public Module, public RemoteBitrateObserver {
   // This class collects feedback from all streams sent to a peer (via
   // RTCPBandwidthObservers). It does one  aggregated send side bandwidth
   // estimation and divide the available bitrate between all its registered
@@ -78,8 +78,6 @@
                              int min_bitrate_bps,
                              int max_bitrate_bps) = 0;
 
-  virtual void OnDelayBasedBweResult(const DelayBasedBwe::Result& result) = 0;
-
   // Gets the available payload bandwidth in bits per second. Note that
   // this bandwidth excludes packet headers.
   virtual bool AvailableBandwidth(uint32_t* bandwidth) const = 0;