chrome/browser/ash/sync/split_settings_sync_field_trial.h

// Copyright 2020 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.

#ifndef CHROME_BROWSER_ASH_SYNC_SPLIT_SETTINGS_SYNC_FIELD_TRIAL_H_
#define CHROME_BROWSER_ASH_SYNC_SPLIT_SETTINGS_SYNC_FIELD_TRIAL_H_

class PrefRegistrySimple;
class PrefService;

namespace base {
class FeatureList;
}  // namespace base

namespace split_settings_sync_field_trial {

// Registers preferences.
void RegisterLocalStatePrefs(PrefRegistrySimple* registry);

// Creates a field trial to control the SplitSettingsSync feature. The trial is
// client controlled because SplitSettingsSync controls the out-of-box
// experience (OOBE) sync consent dialog, which shows up before a variations
// seed is available.
//
// The trial group chosen on first run is persisted to local state prefs and
// reused on subsequent runs. This keeps the in-session sync settings UI stable
// between runs. Local state prefs can be reset via powerwash, which will result
// in re-randomization, but this also sends the user through the first-run flow
// again and they will see the appropriate consent flow.
//
// Persisting the group also avoids a subtle corner case: A user could be
// randomized to SplitSettingsSync, opt-in to sync during OOBE, then turn off OS
// sync in OS settings but leave "Sync everything" enabled in browser settings.
// If they were re-randomized to non-SplitSettingsSync on a future login, then
// the OS sync data types would go back to being controlled by browser sync
// settings, and those OS types would be re-enabled even though the user had
// them disabled.
//
// Launch bug for the SplitSettingsSync feature: https://crbug.com/1020731
void Create(base::FeatureList* feature_list, PrefService* local_state);

}  // namespace split_settings_sync_field_trial

#endif  // CHROME_BROWSER_ASH_SYNC_SPLIT_SETTINGS_SYNC_FIELD_TRIAL_H_