Make Interaction Media Features MQ dynamic on Windows.

content/browser/renderer_host/input/input_device_change_observer.h

+// Copyright (c) 2017 The Chromium Authors. All rights reserved.

[jam, 2017/04/10 15:01:06]

no "(c)" per updated header guidelines

+// 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_CHANGE_OBSERVER_H_
+#define CONTENT_BROWSER_RENDERER_HOST_INPUT_INPUT_DEVICE_CHANGE_OBSERVER_H_
+
+#include "content/public/browser/render_view_host.h"
+#include "ui/events/devices/input_device_event_observer.h"
+
+namespace content {
+class CONTENT_EXPORT InputDeviceChangeObserver

[jam, 2017/04/10 15:01:06]

I don't think the export is needed since you're not instantiating it in a test.

please add comments to the class explaining what it does.

+    : public ui::InputDeviceEventObserver {
+ public:
+  InputDeviceChangeObserver(RenderViewHost* rvh);
+  ~InputDeviceChangeObserver() override;
+
+  // InputDeviceEventObserver public overrrides
+  void OnTouchscreenDeviceConfigurationChanged() override;
+  void OnKeyboardDeviceConfigurationChanged() override;
+  void OnMouseDeviceConfigurationChanged() override;
+  void OnTouchpadDeviceConfigurationChanged() override;
+
+ private:
+  RenderViewHost* render_view_host_;
+  void notifyRenderViewHost();
+  DISALLOW_COPY_AND_ASSIGN(InputDeviceChangeObserver);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_RENDERER_HOST_INPUT_INPUT_DEVICE_CHANGE_OBSERVER_H_