Increase size of trial and increase its duration.

chrome/browser/trials/http_throttling_trial.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/trials/http_throttling_trial.h"
 
 #include "base/metrics/field_trial.h"
 #include "chrome/browser/prefs/pref_service.h"
 #include "chrome/common/pref_names.h"
 
 void CreateHttpThrottlingTrial(PrefService* prefs) {
   DCHECK(prefs);
 
   // We only use one-time randomization, meaning each client will be put
   // in the same group on every startup, so that users do not have a situation
   // where they are intermittently in the experiment group, and have problems
   // because of throttling, then turn off their browser to fix the problem,
   // come back, and cannot figure out why they had problems (because throttling
   // will most likely by then be turned off).  A lesser concern is that if
   // we didn't use one-time randomization, users might notice the preference
   // in about:net-internals toggling from one state to the other.
   if (!base::FieldTrialList::IsOneTimeRandomizationEnabled())
     return;
 
-  // Probability for each trial group (the experiment and the control) is 5%.
-  const base::FieldTrial::Probability kEachGroupProbability = 5;
+  // Probability for each trial group (the experiment and the control) is 25%.
+  const base::FieldTrial::Probability kEachGroupProbability = 25;
   const base::FieldTrial::Probability kTotalProbability = 100;
-  // Disable trial a couple of days before M14 branch point.
+  // Disable trial a couple of days before M15 branch point.
   scoped_refptr<base::FieldTrial> trial(new base::FieldTrial(
-      "HttpThrottlingEnabled", kTotalProbability, "Default", 2011, 7, 23));
+      "HttpThrottlingEnabled", kTotalProbability, "Default", 2011, 9, 20));
   trial->UseOneTimeRandomization();
 
   // If the user has touched the control for whether throttling is enabled
   // or not, we only allow the Default group for the trial, and we do not
   // modify the value of prefs::kHttpThrottlingEnabled.
   if (prefs->GetBoolean(prefs::kHttpThrottlingMayExperiment)) {
     int experiment_group =
         trial->AppendGroup("Experiment", kEachGroupProbability);
 
-    // The behavior for the control group is the same as for the default group.
-    // The point of having the control group is that it's the same size as
-    // the experiment group and selected the same way, so we get an
+    // The behavior for the control group is mostly the same as for
+    // the default group, with the difference that we are guaranteed
+    // that none of the users in the control group have manually
+    // changed the setting (under chrome://net-internals/) for whether
+    // throttling should be turned on or not.  The other point of
+    // having the control group is that it's the same size as the
+    // experiment group and selected the same way, so we get an
     // apples-to-apples comparison of histograms.
     trial->AppendGroup("Control", kEachGroupProbability);
 
     prefs->SetBoolean(prefs::kHttpThrottlingEnabled,
                       trial->group() == experiment_group);
   }
 }