Make Interaction Media Features MQ dynamic on Windows.

ui/events/devices/input_device_observer_win.h

+// Copyright 2017 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 CONTENT_BROWSER_RENDERER_HOST_INPUT_INPUT_DEVICE_OBSERVER_WIN_H_
+#define CONTENT_BROWSER_RENDERER_HOST_INPUT_INPUT_DEVICE_OBSERVER_WIN_H_
+
+#include "base/observer_list.h"
+#include "base/win/registry.h"
+#include "ui/events/devices/input_device_event_observer.h"
+
+namespace base {
+template <typename T>
+struct DefaultSingletonTraits;
+}
+
+namespace ui {
+class EVENTS_DEVICES_EXPORT InputDeviceObserverWin {

[sadrul, 2017/05/10 01:38:32]

Can this be an InputDeviceManager? e.g.

class InputDeviceManagerWin : public InputDeviceManager {
};

+ public:
+  static InputDeviceObserverWin* GetInstance();
+  ~InputDeviceObserverWin();
+
+  void AddObserver(InputDeviceEventObserver* observer);
+  void RemoveObserver(InputDeviceEventObserver* observer);
+
+ protected:
+  InputDeviceObserverWin();
+
+ private:
+  void OnRegistryKeyChanged(base::win::RegKey* key);
+  bool IsSlateModeEnabled(base::win::RegKey* key);
+  void NotifyObserversKeyboardDeviceConfigurationChanged();
+  void NotifyObserversTouchpadDeviceConfigurationChanged();
+
+  std::unique_ptr<base::win::RegKey> registry_key_;
+  base::ObserverList<InputDeviceEventObserver> observers_;
+  bool slate_mode_enabled_;
+
+  friend struct base::DefaultSingletonTraits<InputDeviceObserverWin>;
+
+  base::WeakPtrFactory<InputDeviceObserverWin> weak_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(InputDeviceObserverWin);
+};
+
+}  // namespace ui
+
+#endif  // CONTENT_BROWSER_RENDERER_HOST_INPUT_INPUT_DEVICE_OBSERVER_WIN_H_