Port Chromium OS touch noise filtering to Chromium

ui/events/ozone/evdev/touch_noise/far_apart_taps_touch_noise_filter.h

+// Copyright 2015 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_OZONE_EVDEV_TOUCH_NOISE_FAR_APART_TAPS_TOUCH_NOISE_FILTER_H_
+#define UI_EVENTS_OZONE_EVDEV_TOUCH_NOISE_FAR_APART_TAPS_TOUCH_NOISE_FILTER_H_
+
+#include "base/macros.h"
+#include "base/time/time.h"
+#include "ui/events/ozone/evdev/touch_noise/touch_noise_filter.h"
+
+namespace ui {
+
+class FarApartTapsTouchNoiseFilter : public TouchNoiseFilter {
+public:
+  FarApartTapsTouchNoiseFilter() {}
+  ~FarApartTapsTouchNoiseFilter() override {}
+
+  // TouchNoiseFilter:
+  void Filter(const std::vector<InProgressTouchEvdev>& touches,
+              base::TimeDelta time,
+              std::bitset<kNumTouchEvdevSlots>* slots_with_noise) override;
+
+private:
+  struct Tap {
+    Tap() : x(0), y(0) {}
+    Tap(base::TimeDelta start, int x, int y)
+        : start(start), x(x), y(y) {}
+
+    bool is_valid() const { return start != base::TimeDelta(); }
+    void Invalidate() { start = base::TimeDelta(); }
+
+    base::TimeDelta start;
+    float x;
+    float y;
+  };
+
+  // Tracks in progress taps in slots.
+  Tap tracked_taps_[kNumTouchEvdevSlots];
+
+  DISALLOW_COPY_AND_ASSIGN(FarApartTapsTouchNoiseFilter);
+};
+
+}  // namespace ui
+
+#endif  // UI_EVENTS_OZONE_EVDEV_TOUCH_NOISE_FAR_APART_TAPS_TOUCH_NOISE_FILTER_H_