Forward declare base::Time in uniformity trials.

chrome/common/metrics/variations/uniformity_field_trials.cc

 // Copyright (c) 2013 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/common/metrics/variations/uniformity_field_trials.h"
 
 #include "base/metrics/field_trial.h"

[tfarina, 2013/03/05 16:46:24]

do you want to include base/time.h? now here?

[SteveT, 2013/03/05 17:54:24]

Done.

 #include "base/stringprintf.h"
 #include "chrome/common/metrics/variations/variations_util.h"
 
 namespace {
 
 // Set up a uniformity field trial. |one_time_randomized| indicates if the
 // field trial is one-time randomized or session-randomized. |trial_name_string|
 // must contain a "%d" since the percentage of the group will be inserted in
 // the trial name. |num_trial_groups| must be a divisor of 100 (e.g. 5, 20)
 void SetupSingleUniformityFieldTrial(
@@ skipping 44 matching lines @@
 
   // Now that all groups have been appended, call group() on the trial to
   // ensure that our trial is registered. This resolves an off-by-one issue
   // where the default group never gets chosen if we don't "use" the trial.
   const int chosen_group = trial->group();
   DVLOG(1) << "Chosen Group: " << chosen_group;
 }
 
 // Setup a 50% uniformity trial for new installs only. This is accomplished by
 // disabling the trial on clients that were installed before a specified date.
 void SetupNewInstallUniformityTrial(const base::Time& install_date) {

[tfarina, 2013/03/05 16:46:24]

do you want to pass by value here too?

[SteveT, 2013/03/05 17:54:24]

Done.

   const base::Time::Exploded kStartDate = {
     2012, 11, 0, 6,  // Nov 6, 2012
     0, 0, 0, 0       // 00:00:00.000
   };
   scoped_refptr<base::FieldTrial> trial(
       base::FieldTrialList::FactoryGetFieldTrial(
           "UMA-New-Install-Uniformity-Trial", 100, "Disabled",
           2015, 1, 1, NULL));
   trial->UseOneTimeRandomization();
   trial->AppendGroup("Control", 50);
   trial->AppendGroup("Experiment", 50);
   const base::Time start_date = base::Time::FromLocalExploded(kStartDate);
   if (install_date < start_date)
     trial->Disable();
   else
     trial->group();
 }
 
 }  // namespace
 
 namespace chrome_variations {
 
-void SetupUniformityFieldTrials(const base::Time& install_date) {
+void SetupUniformityFieldTrials(const base::Time install_date) {
   // One field trial will be created for each entry in this array. The i'th
   // field trial will have |trial_sizes[i]| groups in it, including the default
   // group. Each group will have a probability of 1/|trial_sizes[i]|.
   const int num_trial_groups[] = { 100, 20, 10, 5, 2 };
 
   // Declare our variation ID bases along side this array so we can loop over it
   // and assign the IDs appropriately. So for example, the 1 percent experiments
   // should have a size of 100 (100/100 = 1).
   const chrome_variations::VariationID trial_base_ids[] = {
     chrome_variations::UNIFORMITY_1_PERCENT_BASE,
@@ skipping 13 matching lines @@
   // Setup a 5% session-randomized uniformity trial.
   const std::string kSessionRandomizedTrialName =
       "UMA-Session-Randomized-Uniformity-Trial-%d-Percent";
   SetupSingleUniformityFieldTrial(false, kSessionRandomizedTrialName,
       chrome_variations::UNIFORMITY_SESSION_RANDOMIZED_5_PERCENT_BASE, 20);
 
   SetupNewInstallUniformityTrial(install_date);
 }
 
 }  // namespace chrome_variations