UMA stats for stylus usage

ash/wm/stylus_metrics_recorder.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_WM_STYLUS_METRICS_RECORDER_H_
-#define ASH_WM_STYLUS_METRICS_RECORDER_H_
-
-#include <memory>
-
-#include "base/macros.h"
-#include "ui/events/event_handler.h"
-
-namespace ash {
-
-// An event recorder that record stylus related metrics.
-class StylusMetricsRecorder : public ui::EventHandler {
- public:
-  StylusMetricsRecorder();
-  ~StylusMetricsRecorder() override;
-
- private:
-  // ui::EventHandler:
-  void OnMouseEvent(ui::MouseEvent* event) override;
-  void OnTouchEvent(ui::TouchEvent* event) override;
-
-  void RecordUMA(ui::EventPointerType type);
-
-  DISALLOW_COPY_AND_ASSIGN(StylusMetricsRecorder);
-};
-
-}  // namespace ash
-
-#endif  // ASH_WM_STYLUS_METRICS_RECORDER_H_