1 // Copyright 2016 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #include "components/variations/child_process_field_trial_syncer.h" 6 7 #include <set> 8 #include <utility> 9 10 #include "base/base_switches.h" 11 #include "base/command_line.h" 12 #include "components/variations/variations_crash_keys.h" 13 14 namespace variations { 15 ChildProcessFieldTrialSyncer(base::FieldTrialList::Observer * observer)16ChildProcessFieldTrialSyncer::ChildProcessFieldTrialSyncer( 17 base::FieldTrialList::Observer* observer) 18 : observer_(observer) {} 19 ~ChildProcessFieldTrialSyncer()20ChildProcessFieldTrialSyncer::~ChildProcessFieldTrialSyncer() {} 21 InitFieldTrialObserving(const base::CommandLine & command_line)22void ChildProcessFieldTrialSyncer::InitFieldTrialObserving( 23 const base::CommandLine& command_line) { 24 // Set up initial set of crash dump data for field trials in this process. 25 variations::InitCrashKeys(); 26 27 // Listen for field trial activations to report them to the browser. 28 base::FieldTrialList::AddObserver(observer_); 29 30 // Some field trials may have been activated before this point. Notify the 31 // browser of these activations now. To detect these, take the set difference 32 // of currently active trials with the initially active trials. 33 base::FieldTrial::ActiveGroups initially_active_trials; 34 base::FieldTrialList::GetInitiallyActiveFieldTrials(command_line, 35 &initially_active_trials); 36 std::set<std::string> initially_active_trials_set; 37 for (const auto& entry : initially_active_trials) { 38 initially_active_trials_set.insert(std::move(entry.trial_name)); 39 } 40 41 base::FieldTrial::ActiveGroups current_active_trials; 42 base::FieldTrialList::GetActiveFieldTrialGroups(¤t_active_trials); 43 for (const auto& trial : current_active_trials) { 44 if (!base::Contains(initially_active_trials_set, trial.trial_name)) 45 observer_->OnFieldTrialGroupFinalized(trial.trial_name, trial.group_name); 46 } 47 } 48 OnSetFieldTrialGroup(const std::string & trial_name,const std::string & group_name)49void ChildProcessFieldTrialSyncer::OnSetFieldTrialGroup( 50 const std::string& trial_name, 51 const std::string& group_name) { 52 base::FieldTrial* trial = 53 base::FieldTrialList::CreateFieldTrial(trial_name, group_name); 54 // Ensure the trial is marked as "used" by calling group() on it if it is 55 // marked as activated. 56 trial->group(); 57 } 58 59 } // namespace variations 60