Avoid cluster set up at max bitrate at start

webrtc/modules/congestion_controller/probe_controller.cc

Index: webrtc/modules/congestion_controller/probe_controller.cc
diff --git a/webrtc/modules/congestion_controller/probe_controller.cc b/webrtc/modules/congestion_controller/probe_controller.cc
index cf7f3e1b6157b28f4250e7451cc3cf630b04e09f..e91e06efd555c9f8a0e9e852ad4979ee9088e1cc 100644
--- a/webrtc/modules/congestion_controller/probe_controller.cc
+++ b/webrtc/modules/congestion_controller/probe_controller.cc
@@ -54,11 +54,13 @@ void ProbeController::SetBitrates(int min_bitrate_bps,
   }
 
   // Only do probing if:
-  //   - we are mid-call, which we consider to be if
-  //     |estimated_bitrate_bps_| != 0, and
-  //   - the current bitrate is lower than the new |max_bitrate_bps|, and
-  //   - we actually want to increase the |max_bitrate_bps_|.
-  if (estimated_bitrate_bps_ != 0 && estimated_bitrate_bps_ < max_bitrate_bps &&
+  //   we are mid-call, which we consider to be if
+  //     exponential probing is not active and
+  //     |estimated_bitrate_bps_| is valid (> 0) and
+  //     the current bitrate is lower than the new |max_bitrate_bps|, and
+  //     we actually want to increase the |max_bitrate_bps_|.
+  if (state_ != State::kWaitingForProbingResult &&
+      estimated_bitrate_bps_ != 0 && estimated_bitrate_bps_ < max_bitrate_bps &&
       max_bitrate_bps > max_bitrate_bps_) {
     InitiateProbing({max_bitrate_bps}, kExponentialProbingDisabled);
   }