Auto open and close the palette on an eject event.

ash/common/system/chromeos/palette/eject_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_COMMON_SYSTEM_CHROMEOS_PALETTE_EJECT_CONTROLLER_H_
+#define ASH_COMMON_SYSTEM_CHROMEOS_PALETTE_EJECT_CONTROLLER_H_
+
+#include "ash/ash_export.h"
+#include "base/callback.h"
+#include "base/macros.h"
+#include "ui/events/devices/input_device_event_observer.h"
+#include "ui/events/devices/input_device_manager.h"
+
+namespace ash {
+
+// This class observes input device changes for the palette.
+class ASH_EXPORT EjectController : public ui::InputDeviceEventObserver {
+ public:
+  using OnEjectCallback = base::Callback<void(ui::StylusState)>;
+
+  EjectController(const OnEjectCallback& on_eject);

[oshima, 2016/08/24 23:38:50]

nit: explicit

[jdufault, 2016/08/24 23:54:07]

Done.

+  ~EjectController() override;
+
+ private:
+  // ui::InputDeviceObserver:
+  void OnStylusStateChanged(ui::StylusState state) override;
+
+  OnEjectCallback on_eject_;
+
+  DISALLOW_COPY_AND_ASSIGN(EjectController);
+};
+
+}  // namespace ash
+
+#endif  // ASH_COMMON_SYSTEM_CHROMEOS_PALETTE_EJECT_CONTROLLER_H_