Field trial synchronization to PPAPI process.

chrome/common/variations/child_process_field_trial_syncer.cc

-// Copyright 2016 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/variations/child_process_field_trial_syncer.h"
-
-#include <set>
-#include <utility>
-
-#include "base/base_switches.h"
-#include "base/command_line.h"
-#include "components/variations/variations_util.h"
-#include "content/public/common/content_switches.h"
-
-namespace chrome_variations {
-
-ChildProcessFieldTrialSyncer::ChildProcessFieldTrialSyncer(
-    base::FieldTrialList::Observer* observer)
-    : observer_(observer) {}
-
-ChildProcessFieldTrialSyncer::~ChildProcessFieldTrialSyncer() {}
-
-void ChildProcessFieldTrialSyncer::InitFieldTrialObserving(
-    const base::CommandLine& command_line) {
-  // In single-process mode, there is no need to synchronize trials to the
-  // browser process (because it's the same process), so this class is a no-op.
-  if (command_line.HasSwitch(switches::kSingleProcess))
-    return;
-
-  // Set up initial set of crash dump data for field trials in this process.
-  variations::SetVariationListCrashKeys();
-
-  // Listen for field trial activations to report them to the browser.
-  base::FieldTrialList::AddObserver(observer_);
-
-  // Some field trials may have been activated before this point. Notify the
-  // browser of these activations now. To detect these, take the set difference
-  // of currently active trials with the initially active trials.
-  base::FieldTrial::ActiveGroups initially_active_trials;
-  base::FieldTrialList::GetInitiallyActiveFieldTrials(command_line,
-                                                      &initially_active_trials);
-  std::set<std::string> initially_active_trials_set;
-  for (const auto& entry : initially_active_trials) {
-    initially_active_trials_set.insert(std::move(entry.trial_name));
-  }
-
-  base::FieldTrial::ActiveGroups current_active_trials;
-  base::FieldTrialList::GetActiveFieldTrialGroups(&current_active_trials);
-  for (const auto& trial : current_active_trials) {
-    if (!base::ContainsKey(initially_active_trials_set, trial.trial_name))
-      observer_->OnFieldTrialGroupFinalized(trial.trial_name, trial.group_name);
-  }
-}
-
-void ChildProcessFieldTrialSyncer::OnSetFieldTrialGroup(
-    const std::string& trial_name,
-    const std::string& group_name) {
-  base::FieldTrial* trial =
-      base::FieldTrialList::CreateFieldTrial(trial_name, group_name);
-  // Ensure the trial is marked as "used" by calling group() on it if it is
-  // marked as activated.
-  trial->group();
-  variations::SetVariationListCrashKeys();
-}
-
-}  // namespace chrome_variations