WIP: memory coordinator: Check /dev/chromeos-low-mem to determine memory condition

base/memory/low_memory_observer_chromeos.h

+// 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.
+
+#ifndef BASE_MEMORY_LOW_MEMORY_OBSERVER_CHROMEOS_H_
+#define BASE_MEMORY_LOW_MEMORY_OBSERVER_CHROMEOS_H_
+
+#include "base/base_export.h"
+#include "base/files/scoped_file.h"
+
+namespace base {
+namespace chromeos {
+
+// TODO(bashi): Write description of the class.
+class BASE_EXPORT LowMemoryObserver {
+ public:
+  LowMemoryObserver();
+  ~LowMemoryObserver();
+
+  // Returns true when the kernel low memory observer is available.
+  bool is_valid() const { return low_mem_file_.is_valid(); }
+
+  // Checks if the kernel has detected a low memory situation. This will be
+  // called less than once a second.
+  bool IsLowMemoryCondition() const;
+
+ private:
+  ScopedFD low_mem_file_;
+
+  DISALLOW_COPY_AND_ASSIGN(LowMemoryObserver);
+};
+
+}  // namespace chromeos
+}  // namespace base
+
+#endif  // BASE_MEMORY_LOW_MEMORY_OBSERVER_CHROMEOS_H_