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

webrtc/modules/congestion_controller/congestion_controller_unittest.cc

Index: webrtc/modules/congestion_controller/congestion_controller_unittest.cc
diff --git a/webrtc/modules/congestion_controller/congestion_controller_unittest.cc b/webrtc/modules/congestion_controller/congestion_controller_unittest.cc
index e840294d9f09a96da12b5631606ab717c2227e16..e5102e62484009efc68525052bf05af283ce8c64 100644
--- a/webrtc/modules/congestion_controller/congestion_controller_unittest.cc
+++ b/webrtc/modules/congestion_controller/congestion_controller_unittest.cc
@@ -11,6 +11,7 @@
 #include "webrtc/call/mock/mock_rtc_event_log.h"
 #include "webrtc/modules/bitrate_controller/include/bitrate_controller.h"
 #include "webrtc/modules/congestion_controller/include/congestion_controller.h"
+#include "webrtc/modules/congestion_controller/include/defines.h"
 #include "webrtc/modules/congestion_controller/include/mock/mock_congestion_controller.h"
 #include "webrtc/modules/pacing/mock/mock_paced_sender.h"
 #include "webrtc/modules/remote_bitrate_estimator/include/mock/mock_remote_bitrate_observer.h"
@@ -135,10 +136,11 @@ TEST_F(CongestionControllerTest, ResetBweAndBitrates) {
   controller_->ResetBweAndBitrates(new_bitrate, -1, -1);
 
   // If the bitrate is reset to -1, the new starting bitrate will be
-  // the minimum default bitrate 10000bps.
-  int min_default_bitrate = 10000;
-  EXPECT_CALL(observer_, OnNetworkChanged(min_default_bitrate, _, _));
-  EXPECT_CALL(*pacer_, SetEstimatedBitrate(min_default_bitrate));
+  // the minimum default bitrate kMinBitrateBps.
+  EXPECT_CALL(observer_,
+              OnNetworkChanged(congestion_controller::kMinBitrateBps, _, _));
+  EXPECT_CALL(*pacer_,
+              SetEstimatedBitrate(congestion_controller::kMinBitrateBps));
   controller_->ResetBweAndBitrates(-1, -1, -1);
 }