Revert of Intorduce PowerButtonObserver API

athena/system/power_button_controller.h

+// 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_SYSTEM_POWER_BUTTON_CONTROLLER_H_
+#define ATHENA_SYSTEM_POWER_BUTTON_CONTROLLER_H_
+
+#include "base/memory/scoped_ptr.h"
+#include "base/time/time.h"
+#include "base/timer/timer.h"
+#include "chromeos/dbus/power_manager_client.h"
+
+namespace aura {
+class Window;
+}
+
+namespace views {
+class Widget;
+}
+
+namespace athena {
+
+// Shuts down in response to the power button being pressed.
+class PowerButtonController : public chromeos::PowerManagerClient::Observer {
+ public:
+  explicit PowerButtonController(aura::Window* dialog_container);
+  virtual ~PowerButtonController();
+
+ private:
+  enum State {
+    // Releasing the power button sends a suspend request.
+    STATE_SUSPEND_ON_RELEASE,
+
+    // A warning that the device is about to be shutdown is visible. Releasing
+    // the power button does not send a suspend or a shutdown request.
+    STATE_SHUTDOWN_WARNING_VISIBLE,
+
+    // A D-Bus shutdown request has been sent. Shutdown cannot be canceled.
+    STATE_SHUTDOWN_REQUESTED,
+
+    STATE_OTHER
+  };
+
+  // Shows the shutdown warning dialog.
+  void ShowShutdownWarningDialog();
+
+  // Requests shutdown.
+  void Shutdown();
+
+  // chromeos::PowerManagerClient::Observer:
+  virtual void BrightnessChanged(int level, bool user_initiated) override;
+  virtual void PowerButtonEventReceived(
+      bool down,
+      const base::TimeTicks& timestamp) override;
+
+  // |shutdown_warning_message_|'s parent container.
+  aura::Window* warning_message_container_;
+
+  // Shows a warning that the device is about to be shutdown.
+  scoped_ptr<views::Widget> shutdown_warning_message_;
+
+  // Whether the screen brightness was reduced to 0%.
+  bool brightness_is_zero_;
+
+  // The last time at which the screen brightness was 0%.
+  base::TimeTicks zero_brightness_end_time_;
+
+  State state_;
+
+  base::OneShotTimer<PowerButtonController> timer_;
+
+  DISALLOW_COPY_AND_ASSIGN(PowerButtonController);
+};
+
+}  // namespace athena
+
+#endif  // ATHENA_SYSTEM_POWER_BUTTON_CONTROLLER_H_