relnote: Deprecate --quic_auto_tune_receive_window.

net/quic/quic_flow_controller.cc

Index: net/quic/quic_flow_controller.cc
diff --git a/net/quic/quic_flow_controller.cc b/net/quic/quic_flow_controller.cc
index 30c5386f53a2aece2cff1b00caca8c8d0a87914d..184c55163743ecdbc173f1ddb7bb330157e67391 100644
--- a/net/quic/quic_flow_controller.cc
+++ b/net/quic/quic_flow_controller.cc
@@ -109,10 +109,6 @@ void QuicFlowController::MaybeIncreaseMaxWindowSize() {
   // upper bound).  For simplicity this algorithm is deliberately asymmetric, in
   // that it may increase window size but never decreases.
 
-  if (!FLAGS_quic_auto_tune_receive_window) {
-    return;
-  }
-
   // Keep track of timing between successive window updates.
   QuicTime now = connection_->clock()->ApproximateNow();
   QuicTime prev = prev_window_update_time_;