Show notifications on low disk space.

chrome/browser/chromeos/ui/low_disk_notification.h

+// Copyright 2016 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 CHROME_BROWSER_CHROMEOS_UI_LOW_DISK_NOTIFICATION_H_
+#define CHROME_BROWSER_CHROMEOS_UI_LOW_DISK_NOTIFICATION_H_
+
+#include <stdint.h>
+
+#include "base/macros.h"
+#include "base/memory/weak_ptr.h"
+#include "base/time/time.h"
+
+namespace message_center {
+class Notification;
+class MessageCenter;
+}
+
+namespace chromeos {
+
+// LowDiskNotification manages the notification informing the user of low disk
+// space.  It is responsible for both creating the notifications in message
+// center as well as throttling notifications shown to the user.
+// This class should be created after DBus has been initialized and destroyed
+// before DBus has been shutdown.
+class LowDiskNotification {
+ public:
+  // Registers this class as the CryptohomeClient LowDiskSpaceHandler.
+  LowDiskNotification();
+  // Resets CryptohomeClient LowDiskSpaceHandler.
+  ~LowDiskNotification();
+
+  // Called when the device is running low on disk space.  This is responsible
+  // for deciding whether a notification should be shown or not and showing it
+  // if appropriate.
+  void OnLowDiskSpace(uint64_t free_disk_bytes);
+
+ private:
+  friend class LowDiskNotificationTest;
+
+  enum Severity { NONE = -1, MEDIUM = 0, HIGH = 1 };
+
+  // Creates a notification for the specified severity.  If the severity does
+  // not match a known value MEDIUM is used by default.
+  std::unique_ptr<message_center::Notification> CreateNotification(
+      Severity severity);

[satorux1, 2016/06/28 05:53:27]

nit: adds a blank line between functions?

[dspaid, 2016/06/28 06:29:53]

Done.

+  // Gets the severity of the low disk status based on the amount of free space
+  // left on the disk.
+  Severity GetSeverity(uint64_t free_disk_bytes);
+  // Sets the MessageCenter instance to use.  Should only be used in tests.
+  void SetMessageCenterForTest(message_center::MessageCenter* message_center);
+  // Sets the minimum time to wait between notifications of the same severity.
+  // Should only be used in tests.
+  void SetNotificationIntervalForTest(base::TimeDelta interval);
+
+  base::Time last_notification_time_;
+  Severity last_notification_severity_;
+  message_center::MessageCenter* message_center_;
+  base::TimeDelta notification_interval_;
+  base::WeakPtrFactory<LowDiskNotification> weak_ptr_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(LowDiskNotification);
+};
+
+}  // namespace chromeos
+
+#endif  // CHROME_BROWSER_CHROMEOS_UI_LOW_DISK_NOTIFICATION_H_