Remove unused variable

This makes android bots fail and blocks chromium to webrtc roll: https://webrtc-review.googlesource.com/c/src/+/235484/. Unused variable was there for a while. This was probably triggered by Chromium enabling -Wunused-but-set-variable on the toolchain level.

Bug: b/203383377
Change-Id: I50e1c7852def90501694cba57d3a3611c2ffa149
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/235377
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Reviewed-by: Sebastian Jansson <srte@webrtc.org>
Commit-Queue: Andrey Logvin <landrey@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#35226}
diff --git a/modules/congestion_controller/pcc/monitor_interval.cc b/modules/congestion_controller/pcc/monitor_interval.cc
index 6bc9f4a..de1e2d5 100644
--- a/modules/congestion_controller/pcc/monitor_interval.cc
+++ b/modules/congestion_controller/pcc/monitor_interval.cc
@@ -70,13 +70,10 @@
     return 0;
   }
   double sum_times = 0;
-  double sum_delays = 0;
   for (const ReceivedPacket& packet : received_packets_) {
     double time_delta_us =
         (packet.sent_time - received_packets_[0].sent_time).us();
-    double delay = packet.delay.us();
     sum_times += time_delta_us;
-    sum_delays += delay;
   }
   double sum_squared_scaled_time_deltas = 0;
   double sum_scaled_time_delta_dot_delay = 0;