chromium/components/memory_pressure/memory_pressure_voter.h

// Copyright 2019 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef COMPONENTS_MEMORY_PRESSURE_MEMORY_PRESSURE_VOTER_H_
#define COMPONENTS_MEMORY_PRESSURE_MEMORY_PRESSURE_VOTER_H_

#include <array>
#include <optional>

#include "base/functional/callback.h"
#include "base/memory/memory_pressure_listener.h"
#include "base/memory/raw_ptr.h"
#include "base/sequence_checker.h"

namespace memory_pressure {

// Interface used by code which actually monitors memory pressure, to inform
// a MemoryPressureAggregator when the pressure they observe changes, or they
// want to trigger a (re-)notification of clients of the current level.
// Voters must be used only from the same sequence as the Aggregator to which
// they are attached.
class MemoryPressureVoter { … };

// Collects votes from MemoryPressureVoters and evaluates them to determine the
// pressure level for the MultiSourceMemoryPressureMonitor, which will own
// and outlive the aggregator. The pressure level is calculated as the most
// critical of all votes collected. This class is not thread safe and should be
// used from a single sequence.
class MemoryPressureVoteAggregator { … };

// Interface used to notify MemoryPressureVoteAggregator's owner of changes to
// vote aggregation.
class MemoryPressureVoteAggregator::Delegate { … };

}  // namespace memory_pressure

#endif  // COMPONENTS_MEMORY_PRESSURE_MEMORY_PRESSURE_VOTER_H_