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// Copyright 2017 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 <set>
#include <string>
#include "base/macros.h"
#include "base/metrics/field_trial.h"
#include "components/variations/variations_associated_data.h"
namespace variations {
// Watches finalization of trials that may have a variation id for the given
// key. Maintains a list of ids for the given key, and invokes a callback every
// time a new id is found. Does not invoke the callback for ids for trials that
// were finalized prior to the construction of a VariationsIdCollection
// instance. Is not thread safe.
class VariationsIdCollection : public base::FieldTrialList::Observer {
// Will not invoke |new_id_callback| for ids that correspond to trials that
// were finalized before construction of this object. Callers may want to
// call |GetIds()| manually after construction to batch the initial ids.
IDCollectionKey collection_key,
base::RepeatingCallback<void(VariationID)> new_id_callback);
~VariationsIdCollection() override;
// base::FieldTrialList::Observer implementation.
void OnFieldTrialGroupFinalized(const std::string& trial_name,
const std::string& group_name) override;
// Returns a set of all variations ids for trials finalized that are part of
// |collection_key_|.
const std::set<VariationID>& GetIds();
const IDCollectionKey collection_key_;
// Will not be set until the end of initialization.
base::RepeatingCallback<void(VariationID)> new_id_callback_;
std::set<VariationID> id_set_;
} // namespace variations