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

webrtc/modules/remote_bitrate_estimator/aimd_rate_control.cc

Index: webrtc/modules/remote_bitrate_estimator/aimd_rate_control.cc
diff --git a/webrtc/modules/remote_bitrate_estimator/aimd_rate_control.cc b/webrtc/modules/remote_bitrate_estimator/aimd_rate_control.cc
index f83cddc617862b56ca50131895e97921084178b2..2e7b95f090145850f3474e2802c7353a72607731 100644
--- a/webrtc/modules/remote_bitrate_estimator/aimd_rate_control.cc
+++ b/webrtc/modules/remote_bitrate_estimator/aimd_rate_control.cc
@@ -16,6 +16,7 @@
 
 #include "webrtc/base/checks.h"
 
+#include "webrtc/modules/congestion_controller/include/defines.h"
 #include "webrtc/modules/remote_bitrate_estimator/overuse_detector.h"
 #include "webrtc/modules/remote_bitrate_estimator/include/remote_bitrate_estimator.h"
 #include "webrtc/modules/remote_bitrate_estimator/test/bwe_test_logging.h"
@@ -27,8 +28,7 @@ static const double kWithinIncomingBitrateHysteresis = 1.05;
 static const int64_t kMaxFeedbackIntervalMs = 1000;
 
 AimdRateControl::AimdRateControl()
-    : min_configured_bitrate_bps_(
-          RemoteBitrateEstimator::kDefaultMinBitrateBps),
+    : min_configured_bitrate_bps_(congestion_controller::kMinBitrateBps),
       max_configured_bitrate_bps_(30000000),
       current_bitrate_bps_(max_configured_bitrate_bps_),
       avg_max_bitrate_kbps_(-1.0f),