chrome/browser/chromeos/memory/low_memory_observer.h

   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
  10 namespace chromeos {
  11
  12 class 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.
  25 class 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_