Tablet-like power button behavior on Convertible/Tablet ChromeOS devices

ash/system/chromeos/power/tablet_power_button_controller.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 ASH_SYSTEM_CHROMEOS_POWER_TABLET_POWER_BUTTON_CONTROLLER_H_
+#define ASH_SYSTEM_CHROMEOS_POWER_TABLET_POWER_BUTTON_CONTROLLER_H_
+
+#include "ash/ash_export.h"
+#include "base/macros.h"
+#include "base/time/time.h"
+#include "base/timer/timer.h"
+#include "chromeos/dbus/power_manager_client.h"
+#include "ui/events/devices/input_device_event_observer.h"
+#include "ui/events/event_handler.h"
+
+namespace ash {
+
+class LockStateController;
+
+// Handles power button events on convertible/tablet device. This class is
+// instantiated and used in PowerButtonController.
+class ASH_EXPORT TabletPowerButtonController
+    : public chromeos::PowerManagerClient::Observer,
+      public ui::EventHandler,
+      public ui::InputDeviceEventObserver {
+ public:
+  // Helper class used by tablet power button tests to access internal state.
+  class ASH_EXPORT TestApi {
+   public:
+    explicit TestApi(TabletPowerButtonController* controller);
+    virtual ~TestApi();

[Daniel Erat, 2016/11/10 22:48:55]

this doesn't need to be virtual

[Qiang(Joe) Xu, 2016/11/11 04:39:23]

Done.

+
+    // Returns true when |shutdown_timer_| is running.
+    bool ShutdownTimerIsRunning() const;
+
+    // Emulates |shutdown_timer_| timeout.
+    void TriggerShutdownTimeout();
+
+   private:
+    TabletPowerButtonController* controller_;  // Not owned.
+
+    DISALLOW_COPY_AND_ASSIGN(TestApi);
+  };
+
+  explicit TabletPowerButtonController(LockStateController* controller);
+  ~TabletPowerButtonController() override;
+
+  static TabletPowerButtonController* GetInstance();

[Daniel Erat, 2016/11/10 22:48:55]

if at all possible, please don't introduce new singletons. they cause all sorts
of problems around initialization and destruction order. it's much clearer and
safer to have clear ownership of objects.

[Qiang(Joe) Xu, 2016/11/11 04:39:23]

I see. I make TabletPowerButtonController belongs to ash::Shell now.

+
+  // Returns true if power button events should be handled by this class instead
+  // of PowerButtonController.
+  bool ShouldHandlePowerButtonEvents() const;
+
+  // Handles a power button event.
+  void OnPowerButtonEvent(bool down, const base::TimeTicks& timestamp);
+
+  // Overriden from chromeos::PowerManagerClient::Observer:
+  void PowerManagerRestarted() override;
+  void BrightnessChanged(int level, bool user_initiated) override;
+  void SuspendDone(const base::TimeDelta& sleep_duration) override;
+
+  // Overriden from ui::EventHandler:
+  void OnKeyEvent(ui::KeyEvent* event) override;
+  void OnMouseEvent(ui::MouseEvent* event) override;
+
+  // Overriden from ui::InputDeviceObserver:
+  void OnStylusStateChanged(ui::StylusState state) override;
+
+ private:
+  // Set backlights to |forced_off| if needed.

[Daniel Erat, 2016/11/10 22:48:55]

nit: s/if needed/if they aren't already/

[Qiang(Joe) Xu, 2016/11/11 04:39:23]

Done.

+  void SetBacklightsForcedOff(bool forced_off);
+
+  // Sends a request to powerd to get the backlights forced off state so that
+  // |backlights_forced_off_| can be initialized.
+  void GetInitialBacklightsForcedOff();
+
+  // Initializes |backlights_forced_off_|.
+  void OnGotInitialBacklightsForcedOff(bool is_forced_off);
+
+  // Starts |shutdown_timer_| when the power button is pressed while in
+  // tablet mode.
+  void StartShutdownTimer();
+
+  // Called by |shutdown_timer_| to start the pre-shutdown animation.
+  void OnShutdownTimeout();
+
+  // Locks the screen if the "require password to wake from sleep" pref is set
+  // and locking is possible.
+  void LockScreenIfRequired();
+
+  // True if the brightness level is currently set to off.
+  bool brightness_level_is_zero_ = false;
+
+  // Current forced-off state of backlights.
+  bool backlights_forced_off_ = false;
+
+  // True if the screen was off when the power button was pressed.
+  bool screen_off_when_power_button_down_ = false;
+
+  // Saves the most recent timestamp that powerd is resuming from suspend,
+  // updated in SuspendDone().
+  base::TimeTicks last_resume_time_;
+
+  // Started when the tablet power button is pressed and stopped when it's
+  // released. Runs OnShutdownTimeout() to start shutdown.
+  base::OneShotTimer shutdown_timer_;
+
+  LockStateController* controller_;  // Not owned.
+
+  DISALLOW_COPY_AND_ASSIGN(TabletPowerButtonController);
+};
+
+}  // namespace ash
+
+#endif  // ASH_SYSTEM_CHROMEOS_POWER_TABLET_POWER_BUTTON_CONTROLLER_H_