Add field trial for A/B testing of SSL False Start.

chrome/browser/browser_main.cc

 // Copyright (c) 2011 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 213 matching lines @@
 // This will be called after the command-line has been mutated by about:flags
 void BrowserMainParts::SetupFieldTrials() {
   // Note: make sure to call ConnectionFieldTrial() before
   // ProxyConnectionsFieldTrial().
   ConnectionFieldTrial();
   SocketTimeoutFieldTrial();
   ProxyConnectionsFieldTrial();
   PrefetchAndPrerenderFieldTrial();
   SpdyFieldTrial();
   ConnectBackupJobsFieldTrial();
+  SSLFalseStartFieldTrial();
 }
 
 // This is an A/B test for the maximum number of persistent connections per
 // host. Currently Chrome, Firefox, and IE8 have this value set at 6. Safari
 // uses 4, and Fasterfox (a plugin for Firefox that supposedly configures it to
 // run faster) uses 8. We would like to see how much of an effect this value has
 // on browsing. Too large a value might cause us to run into SYN flood detection
 // mechanisms.
 void BrowserMainParts::ConnectionFieldTrial() {
   const base::FieldTrial::Probability kConnectDivisor = 100;
@@ skipping 178 matching lines @@
   if (parsed_command_line().HasSwitch(switches::kMaxSpdyConcurrentStreams)) {
     int value = 0;
     base::StringToInt(parsed_command_line().GetSwitchValueASCII(
             switches::kMaxSpdyConcurrentStreams),
         &value);
     if (value > 0)
       net::SpdySession::set_max_concurrent_streams(value);
   }
 }
 
+void BrowserMainParts::SSLFalseStartFieldTrial() {
+  if (parsed_command_line().HasSwitch(switches::kDisableSSLFalseStart)) {
+    net::SSLConfigService::DisableFalseStart();
+    return;
+  }
+
+  const base::FieldTrial::Probability kDivisor = 100;
+  base::FieldTrial::Probability falsestart_probability = 50;  // 50/50 trial
+
+  // After July 30, 2011 builds, it will always be in default group.
+  scoped_refptr<base::FieldTrial> trial(
+      new base::FieldTrial(
+          "SSLFalseStart", kDivisor, "FalseStart_enabled", 2011, 7, 30));
+
+  int disabled_group = trial->AppendGroup("FalseStart_disabled",
+                                          falsestart_probability);
+
+  int trial_grp = trial->group();
+  if (trial_grp == disabled_group)
+    net::SSLConfigService::DisableFalseStart();
+}
+
 // Parse the --prerender= command line switch, which controls both prerendering
 // and prefetching.  If the switch is unset, or is set to "auto", then the user
 // is assigned to a field trial.
 void BrowserMainParts::PrefetchAndPrerenderFieldTrial() {
   enum PrerenderOption {
     PRERENDER_OPTION_AUTO,
     PRERENDER_OPTION_DISABLED,
     PRERENDER_OPTION_ENABLED,
     PRERENDER_OPTION_PREFETCH_ONLY,
   };
@@ skipping 1409 matching lines @@
 #if defined(OS_CHROMEOS)
   // To be precise, logout (browser shutdown) is not yet done, but the
   // remaining work is negligible, hence we say LogoutDone here.
   chromeos::BootTimesLoader::Get()->AddLogoutTimeMarker("LogoutDone",
                                                         false);
   chromeos::BootTimesLoader::Get()->WriteLogoutTimes();
 #endif
   TRACE_EVENT_END("BrowserMain", 0, 0);
   return result_code;
 }