1// Copyright (c) 2012 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#ifndef CHROME_BROWSER_CHROMEOS_MEMORY_LOW_MEMORY_OBSERVER_H_
6#define CHROME_BROWSER_CHROMEOS_MEMORY_LOW_MEMORY_OBSERVER_H_
7
8#include "base/memory/ref_counted.h"
9
10namespace chromeos {
11
12class LowMemoryObserverImpl;
13
14////////////////////////////////////////////////////////////////////////////////
15// LowMemoryObserver
16//
17// Class to handle observation of low memory device for changes so that we
18// can get a signal from the kernel about low memory conditions and discard tabs
19// when that happens, instead of waiting for the OOM killer to kill renderers
20// (which is more drastic, but still necessary and possible).
21//
22// This object starts and stops the observation, and can be created or deleted
23// from any thread, but the observation occurs on the FILE thread, and tabs are
24// discarded on the UI thread.
25class LowMemoryObserver {
26 public:
27  LowMemoryObserver();
28  ~LowMemoryObserver();
29
30  void Start();
31  void Stop();
32
33 private:
34  scoped_refptr<LowMemoryObserverImpl> observer_;
35
36  DISALLOW_COPY_AND_ASSIGN(LowMemoryObserver);
37};
38
39}  // namespace chromeos
40
41#endif  // CHROME_BROWSER_CHROMEOS_MEMORY_LOW_MEMORY_OBSERVER_H_
42