Rather than passing initial_flow_control_window all the way down the

net/tools/quic/quic_client_bin.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // A binary wrapper for QuicClient.  Connects to --hostname via --address
 // on --port and requests URLs specified on the command line.
 // Pass --secure to check the certificates using proof verifier.
 // Pass --initial_flow_control_window to specify the size of the initial flow
 // control receive window to advertise to server.
 //
@@ skipping 61 matching lines @@
   }
   VLOG(1) << "server port: " << FLAGS_port
           << " address: " << FLAGS_address
           << " hostname: " << FLAGS_hostname
           << " secure: " << FLAGS_secure;
 
   base::AtExitManager exit_manager;
 
   net::IPAddressNumber addr;
   CHECK(net::ParseIPLiteralToNumber(FLAGS_address, &addr));
+
+  net::QuicConfig config;
+  config.SetInitialFlowControlWindowToSend(FLAGS_initial_flow_control_window);
+
   // TODO(rjshade): Set version on command line.
   net::tools::QuicClient client(
       net::IPEndPoint(addr, FLAGS_port),
       net::QuicServerId(FLAGS_hostname, FLAGS_port, FLAGS_secure,
                         net::PRIVACY_MODE_DISABLED),
-      net::QuicSupportedVersions(), true, FLAGS_initial_flow_control_window);
+      net::QuicSupportedVersions(), true, config);
 
   client.Initialize();
 
   if (!client.Connect()) return 1;
 
   client.SendRequestsAndWaitForResponse(line->GetArgs());
   return 0;
 }