Feature to disable field trials in old versions of Chromium. Field trials...

chrome/browser/net/websocket_experiment/websocket_experiment_runner.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/net/websocket_experiment/websocket_experiment_runner.h"
 
 #include "base/command_line.h"
 #include "base/compiler_specific.h"
 #include "base/message_loop.h"
 #include "base/metrics/field_trial.h"
@@ skipping 10 matching lines @@
 static const char *kExperimentHost = "websocket-experiment.chromium.org";
 static const int kAlternativePort = 61985;
 
 // Hold reference while experiment is running.
 static scoped_refptr<WebSocketExperimentRunner> runner;
 
 /* static */
 void WebSocketExperimentRunner::Start() {
   DCHECK(!runner.get());
 
+  // After June 30, 2011 builds, it will always be in defaut group.
   scoped_refptr<base::FieldTrial> trial(
-      new base::FieldTrial("WebSocketExperiment", 1000));
-  trial->AppendGroup("active", 5);  // 0.5% in active group.
+      new base::FieldTrial("WebSocketExperiment", 1000, "default", 2011, 6,
+          30));
+  int active = trial->AppendGroup("active", 5);  // 0.5% in active group.
 
-  bool run_experiment =
-      (trial->group() != base::FieldTrial::kNotParticipating);
+  bool run_experiment = (trial->group() == active);
 #ifndef NDEBUG
   const CommandLine& command_line = *CommandLine::ForCurrentProcess();
   std::string experiment_host = command_line.GetSwitchValueASCII(
       switches::kWebSocketLiveExperimentHost);
   if (!experiment_host.empty())
     run_experiment = true;
 #else
   run_experiment = false;
 #endif
   if (!run_experiment)
@@ skipping 179 matching lines @@
     Release();
     return;
   }
   task_->SaveResult();
   task_.reset();
 
   DoLoop();
 }
 
 }  // namespace chrome_browser_net_websocket_experiment