QUIC - Add back to code to experiment with delay_tcp_race. By default,

chrome/browser/io_thread.h

 // 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.
 
 #ifndef CHROME_BROWSER_IO_THREAD_H_
 #define CHROME_BROWSER_IO_THREAD_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 312 matching lines @@
     // closed and is considered as a lossy connection. Returns 0 if the default
     // value should be used.
     static float GetQuicPacketLossThreshold(
         const VariationParameters& quic_trial_params);
 
     // Returns the size of the QUIC receive buffer to use, or 0 if the default
     // should be used.
     static int GetQuicSocketReceiveBufferSize(
         const VariationParameters& quic_trial_params);
 
+    // Returns true if QUIC should delay TCP connection when QUIC works.
+    static bool ShouldQuicDelayTcpRace(
+        const VariationParameters& quic_trial_params);
+
     // Returns true if QUIC should close sessions when any of the client's IP
     // addresses change.
     static bool ShouldQuicCloseSessionsOnIpChange(
         const VariationParameters& quic_trial_params);
 
     // Returns the idle connection timeout for QUIC connections.  Returns 0 if
     // there is an error parsing any of the options, or if the default value
     // should be used.
     static int GetQuicIdleConnectionTimeoutSeconds(
         const VariationParameters& quic_trial_params);
@@ skipping 213 matching lines @@
   // Callback for updating data use prefs which needs to be initialized on UI
   // thread and passed to |ChromeNetworkDelegate|.
   metrics::UpdateUsagePrefCallbackType metrics_data_use_forwarder_;
 
   base::WeakPtrFactory<IOThread> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(IOThread);
 };
 
 #endif  // CHROME_BROWSER_IO_THREAD_H_