A/B experiment for re-establishing TCP connections

chrome/browser/browser_main.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 "chrome/browser/browser_main.h"
 
 #include <algorithm>
 #include <string>
 #include <vector>
 
@@ skipping 159 matching lines @@
 void BrowserMainParts::EarlyInitialization() {
   PreEarlyInitialization();
 
   // Note: make sure to call ConnectionFieldTrial() before
   // ProxyConnectionsFieldTrial().
   ConnectionFieldTrial();
   SocketTimeoutFieldTrial();
   ProxyConnectionsFieldTrial();
   SpdyFieldTrial();
   PrefetchFieldTrial();
+  ConnectBackupJobsFieldTrial();
   InitializeSSL();
 
   if (parsed_command_line().HasSwitch(switches::kEnableDNSSECCerts))
     net::SSLConfigService::EnableDNSSEC();
   if (parsed_command_line().HasSwitch(switches::kDisableSSLFalseStart))
     net::SSLConfigService::DisableFalseStart();
   if (parsed_command_line().HasSwitch(switches::kAllowSSLMITMProxies))
     net::SSLConfigService::AllowMITMProxies();
 
   PostEarlyInitialization();
@@ skipping 195 matching lines @@
     trial->AppendGroup("ContentPrefetchDisabled", no_prefetch_probability);
     const int yes_prefetch_grp =
         trial->AppendGroup("ContentPrefetchEnabled",
                            FieldTrial::kAllRemainingProbability);
     const int trial_grp = trial->group();
     ResourceDispatcherHost::set_is_prefetch_enabled(
         trial_grp == yes_prefetch_grp);
   }
 }
 
+// If neither --enable-connect-backup-jobs or --disable-connect-backup-jobs is
+// specified, run an A/B test for automatically establishing backup TCP
+// connections when a certain timeout value is exceeded.
+void BrowserMainParts::ConnectBackupJobsFieldTrial() {
+  if (parsed_command_line().HasSwitch(switches::kEnableConnectBackupJobs)) {
+    net::internal::ClientSocketPoolBaseHelper::set_connect_backup_jobs_enabled(
+        true);
+  } else if (parsed_command_line().HasSwitch(
+        switches::kDisableConnectBackupJobs)) {
+    net::internal::ClientSocketPoolBaseHelper::set_connect_backup_jobs_enabled(
+        false);
+  } else {
+    const FieldTrial::Probability kConnectBackupJobsDivisor = 100;
+    // 50% probability.
+    const FieldTrial::Probability kConnectBackupJobsProbability = 50;
+    scoped_refptr<FieldTrial> trial =
+      new FieldTrial("ConnnectBackupJobs", kConnectBackupJobsDivisor);
+    const int connect_backup_jobs_enabled =
+        trial->AppendGroup("ConnectBackupJobsEnabled",
+            kConnectBackupJobsProbability);
+    trial->AppendGroup("ConnectBackupJobsDisabled",
+                       FieldTrial::kAllRemainingProbability);
+    const int trial_group = trial->group();
+    net::internal::ClientSocketPoolBaseHelper::set_connect_backup_jobs_enabled(
+        trial_group == connect_backup_jobs_enabled);
+  }
+}
+
 // BrowserMainParts: |MainMessageLoopStart()| and related ----------------------
 
 void BrowserMainParts::MainMessageLoopStart() {
   PreMainMessageLoopStart();
 
   main_message_loop_.reset(new MessageLoop(MessageLoop::TYPE_UI));
 
   // TODO(viettrungluu): should these really go before setting the thread name?
   system_monitor_.reset(new SystemMonitor);
   hi_res_timer_manager_.reset(new HighResolutionTimerManager);
@@ skipping 1058 matching lines @@
   metrics->Stop();
 
   // browser_shutdown takes care of deleting browser_process, so we need to
   // release it.
   ignore_result(browser_process.release());
   browser_shutdown::Shutdown();
 
   TRACE_EVENT_END("BrowserMain", 0, 0);
   return result_code;
 }