Sync ui/events to chromium @ https://codereview.chromium.org/1210203002

ui/events/devices/device_hotplug_event_observer.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 UI_EVENTS_DEVICES_DEVICE_HOTPLUG_EVENT_OBSERVER_H_
+#define UI_EVENTS_DEVICES_DEVICE_HOTPLUG_EVENT_OBSERVER_H_
+
+#include <vector>
+
+#include "ui/events/devices/events_devices_export.h"
+
+namespace ui {
+
+struct InputDevice;
+struct KeyboardDevice;
+struct TouchscreenDevice;
+
+// Listener for specific input device hotplug events.
+class EVENTS_DEVICES_EXPORT DeviceHotplugEventObserver {
+ public:
+  virtual ~DeviceHotplugEventObserver() {}
+
+  // On a hotplug event this is called with the list of available touchscreen
+  // devices. The set of touchscreen devices may not have changed.
+  virtual void OnTouchscreenDevicesUpdated(
+      const std::vector<TouchscreenDevice>& devices) = 0;
+
+  // On a hotplug event this is called with the list of available keyboard
+  // devices. The set of keyboard devices may not have changed.
+  virtual void OnKeyboardDevicesUpdated(
+      const std::vector<KeyboardDevice>& devices) = 0;
+
+  // On a hotplug event this is called with the list of available mice. The set
+  // of mice may not have changed.
+  virtual void OnMouseDevicesUpdated(
+      const std::vector<InputDevice>& devices) = 0;
+
+  // On a hotplug event this is called with the list of available touchpads. The
+  // set of touchpads may not have changed.
+  virtual void OnTouchpadDevicesUpdated(
+      const std::vector<InputDevice>& devices) = 0;
+
+  // On completion of the initial startup scan. This means all of the above
+  // OnDevicesUpdated() methods have been called with a complete list.
+  virtual void OnDeviceListsComplete() = 0;
+};
+
+}  // namespace ui
+
+#endif  // UI_EVENTS_DEVICES_DEVICE_HOTPLUG_EVENT_OBSERVER_H_