Set min BWE bitrate form 10kbps to 5kbps and centralize minimum bitrate.

webrtc/modules/congestion_controller/include/defines.h

 /*
  *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
-#include "webrtc/modules/audio_coding/neteq/packet.h"
+#ifndef WEBRTC_MODULES_CONGESTION_CONTROLLER_INCLUDE_DEFINES_H_
+#define WEBRTC_MODULES_CONGESTION_CONTROLLER_INCLUDE_DEFINES_H_
 
 namespace webrtc {
+namespace congestion_controller {
+constexpr int kMinBitrateBps = 5000;
+}  // namespace congestion_controller
+}  // namespace webrtc
 
-Packet::Packet() = default;
-
-Packet::~Packet() = default;
-
-}  // namespace webrtc
+#endif  // WEBRTC_MODULES_CONGESTION_CONTROLLER_INCLUDE_DEFINES_H_