A/B experiment for re-establishing TCP connections

net/socket/client_socket.cc

 // Copyright (c) 2010 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.
 
 #include "net/socket/client_socket.h"
 
+#include "base/field_trial.h"
 #include "base/histogram.h"
 
 namespace net {
 
 ClientSocket::ClientSocket()
     : was_ever_connected_(false),
       omnibox_speculation_(false),
       subresource_speculation_(false),
       was_used_to_transmit_data_(false) {}
 
@@ skipping 17 matching lines @@
     result = 2;
   else if (was_ever_connected_)
     result = 1;
   else
     result = 0;  // Never used, and not really connected.
 
   if (omnibox_speculation_)
     result += 3;
   else if (subresource_speculation_)
     result += 6;
-  UMA_HISTOGRAM_ENUMERATION("Net.PreconnectUtilization", result, 9);
+
+  static const bool connect_backup_jobs_fieldtrial =
+      FieldTrialList::Find("ConnnectBackupJobs") &&
+      !FieldTrialList::Find("ConnnectBackupJobs")->group_name().empty();
+  if (connect_backup_jobs_fieldtrial) {
+    UMA_HISTOGRAM_ENUMERATION(
+        FieldTrial::MakeName("Net.PreconnectUtilization", "ConnnectBackupJobs"),
+        result, 9);
+  }
 }
 
 void ClientSocket::SetSubresourceSpeculation() {
   if (was_used_to_transmit_data_)
     return;
   subresource_speculation_ = true;
 }
 
 void ClientSocket::SetOmniboxSpeculation() {
   if (was_used_to_transmit_data_)
     return;
   omnibox_speculation_ = true;
 }
 
 void ClientSocket::UpdateConnectivityState(bool is_reused) {
   // Record if this connection has every actually connected successfully.
   // Note that IsConnected() won't be defined at destruction time, so we need
   // to record this data now, while the derived class is present.
   was_ever_connected_ |= IsConnected();
   // A socket is_reused only after it has transmitted some data.
   was_used_to_transmit_data_ |= is_reused;
 }
 
 }  // namespace net