Deprecate FLAGS_quic_limit_cubic_cwnd_increase.

net/quic/core/congestion_control/cubic_bytes.cc

Index: net/quic/core/congestion_control/cubic_bytes.cc
diff --git a/net/quic/core/congestion_control/cubic_bytes.cc b/net/quic/core/congestion_control/cubic_bytes.cc
index 91924b06e9f6aca1d9dc359a3c45155e2c964960..ec1c996e2c626520bdd74aeefe27baf4b599ad22 100644
--- a/net/quic/core/congestion_control/cubic_bytes.cc
+++ b/net/quic/core/congestion_control/cubic_bytes.cc
@@ -152,12 +152,10 @@ QuicByteCount CubicBytes::CongestionWindowAfterAck(
 
   QuicByteCount target_congestion_window =
       origin_point_congestion_window_ - delta_congestion_window;
-  if (FLAGS_quic_limit_cubic_cwnd_increase) {
-    // Limit the CWND increase to half the acked bytes.
-    target_congestion_window =
-        min(target_congestion_window,
-            current_congestion_window + acked_bytes_count_ / 2);
-  }
+  // Limit the CWND increase to half the acked bytes.
+  target_congestion_window =
+      min(target_congestion_window,
+          current_congestion_window + acked_bytes_count_ / 2);
 
   DCHECK_LT(0u, estimated_tcp_congestion_window_);
   // Increase the window by Alpha * 1 MSS of bytes every time we ack an