chromium/content/public/browser/swap_metrics_driver.h

// Copyright 2017 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CONTENT_PUBLIC_BROWSER_SWAP_METRICS_DRIVER_H_
#define CONTENT_PUBLIC_BROWSER_SWAP_METRICS_DRIVER_H_

#include <memory>

#include "base/time/time.h"
#include "content/common/content_export.h"

namespace content {

// This class collects metrics about the system's swapping behavior and provides
// these metrics to an associated delegate. Metrics can be platform-specific.
//
// Updated swap metrics can be obtained through Delegate methods in either a
// push-based manner, driven by a periodic base::Timer, or in a synchronous,
// pull-based manner. For receiving periodic updates at a regular frequency, use
// Start() to begin recieiving updates, and Stop() to end them. For obtaining
// updates at specified times, for example over a specific interval or event,
// use InitializeMetrics() at the start, and UpdateMetrics() at any subsequent
// time to immediately and synchronously receive updates. In the case of
// periodic updates, UpdateMetrics() can also be called after Stop() to retrieve
// updated metrics since the last update.
//
// The SwapMetricsDriver API is not thread safe. The Delegate methods run on
// either the sequence on which Start() was called, in the case of periodic
// updates, or the sequence InitializeMetrics() is called on in the case of
// using pull-based updates. In either case, metrics must always be updated on
// the same sequence and subsequent invocations of this API's methods must be
// made on that sequence.
class CONTENT_EXPORT SwapMetricsDriver { … };

}  // namespace content

#endif  // CONTENT_PUBLIC_BROWSER_SWAP_METRICS_DRIVER_H_