Intorduce PowerButtonObserver API

athena/input/power_button_controller.h

Index: athena/input/power_button_controller.h
diff --git a/athena/input/power_button_controller.h b/athena/input/power_button_controller.h
new file mode 100644
index 0000000000000000000000000000000000000000..7550fc43689ff327043fca38b380d0509e777600
--- /dev/null
+++ b/athena/input/power_button_controller.h
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+// Copyright 2014 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 ATHENA_INPUT_POWER_BUTTON_CONTROLLER_H_
+#define ATHENA_INPUT_POWER_BUTTON_CONTROLLER_H_
+
+#include "athena/input/public/accelerator_manager.h"
+#include "athena/input/public/input_manager.h"
+#include "base/observer_list.h"
+#include "base/timer/timer.h"
+#include "chromeos/dbus/power_manager_client.h"
+
+namespace athena {
+
+class PowerButtonController : public chromeos::PowerManagerClient::Observer,
+                              public AcceleratorHandler {
+ public:
+  PowerButtonController();
+  virtual ~PowerButtonController();
+
+  void AddPowerButtonObserver(PowerButtonObserver* observer);
+  void RemovePowerButtonObserver(PowerButtonObserver* observer);
+
+  void InstallAccelerators();
+
+  // A timer callabck to notify the long press event.
+  int SetPowerButtonTimeoutMsForTest(int timeout);
+
+ private:
+  // chromeos::PowerManagerClient::Observer:
+  virtual void BrightnessChanged(int level, bool user_initiated) override;
+  virtual void PowerButtonEventReceived(
+      bool down,
+      const base::TimeTicks& timestamp) override;
+
+  // AcceleratorHandler:
+  virtual bool IsCommandEnabled(int command_id) const override;
+  virtual bool OnAcceleratorFired(int command_id,
+                                  const ui::Accelerator& accelerator) override;
+
+  void NotifyLongPress();
+
+  int power_button_timeout_ms_;
+  ObserverList<PowerButtonObserver> observers_;
+  // The last time at which the screen brightness was 0%.
+  base::TimeTicks zero_brightness_end_time_;
+  bool brightness_is_zero_;
+  base::OneShotTimer<PowerButtonController> timer_;
+
+  DISALLOW_COPY_AND_ASSIGN(PowerButtonController);
+};
+
+}  // namespace athena
+
+#endif  // ATHENA_INPUT_POWER_BUTTON_CONTROLLER_H_