Create A/B test of SDCH...

chrome/browser/renderer_host/browser_render_process_host.cc

 // Copyright (c) 2006-2009 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.
 
 // Represents the browser side of the browser <--> renderer communication
 // channel. There will be one RenderProcessHost per renderer process.
 
 #include "chrome/browser/renderer_host/browser_render_process_host.h"
 
 #include "build/build_config.h"
@@ skipping 293 matching lines @@
   if (profile()->GetExtensionsService()) {
     if (profile()->GetExtensionsService()->extensions()->size() > 0 ||
         profile()->GetExtensionsService()->extensions_enabled())
       cmd_line.AppendSwitch(switches::kEnableExtensions);
   }
 
   // Pass on the browser locale.
   const std::string locale = g_browser_process->GetApplicationLocale();
   cmd_line.AppendSwitchWithValue(switches::kLang, ASCIIToWide(locale));
 
-  // If we run a FieldTrial that we want to pass to the renderer, this is where
-  // the SINGULAR trial name and value should be specified.  Note that only one
-  // such flag should be passed/set in the renderer command line.
-
-  // Today we're watching the impact of DNS on some page load times.
-  FieldTrial* field_trial = FieldTrialList::Find("DnsImpact");
-  if (field_trial && (field_trial->group() != FieldTrial::kNotParticipating))
+  // If we run FieldTrials, we want to pass to their state to the renderer so
+  // that it can act in accordance with each state, or record histograms
+  // relating to the FieldTrial states.
+  std::string field_trial_states;
+  FieldTrialList::StatesToString(&field_trial_states);
+  if (!field_trial_states.empty())
     cmd_line.AppendSwitchWithValue(switches::kForceFieldTestNameAndValue,
-        ASCIIToWide(field_trial->MakePersistentString()));
+        ASCIIToWide(field_trial_states));
 
 #if defined(OS_POSIX)
   const bool has_cmd_prefix =
       browser_command_line.HasSwitch(switches::kRendererCmdPrefix);
   if (has_cmd_prefix) {
     // launch the renderer child with some prefix (usually "gdb --args")
     const std::wstring prefix =
         browser_command_line.GetSwitchValue(switches::kRendererCmdPrefix);
     cmd_line.PrependWrapper(prefix);
   }
@@ skipping 559 matching lines @@
   ExtensionMessageService* ems = ExtensionMessageService::GetInstance(context);
   ems->AddEventListener(event_name, pid());
 }
 
 void BrowserRenderProcessHost::OnExtensionRemoveListener(
     const std::string& event_name) {
   URLRequestContext* context = profile()->GetRequestContext();
   ExtensionMessageService* ems = ExtensionMessageService::GetInstance(context);
   ems->RemoveEventListener(event_name, pid());
 }