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

ui/events/ozone/evdev/touch_noise/touch_noise_finder.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_TOUCH_NOISE_FINDER_H_
+#define UI_EVENTS_OZONE_EVDEV_TOUCH_NOISE_TOUCH_NOISE_FINDER_H_
+
+#include <bitset>
+#include <vector>
+
+#include "base/basictypes.h"
+#include "base/time/time.h"
+#include "ui/events/ozone/evdev/events_ozone_evdev_export.h"
+#include "ui/events/ozone/evdev/touch_evdev_types.h"
+
+namespace ui {
+class TouchNoiseFilter;
+
+// Finds touches which are likely touch noise.
+class EVENTS_OZONE_EVDEV_EXPORT TouchNoiseFinder {
+ public:
+  TouchNoiseFinder();
+  ~TouchNoiseFinder();
+
+  // Updates which ABS_MT_SLOTs are noise. |touches| should contain all of the
+  // in-progress touches at |time| (including noisy touches).
+  // |touches| should have at most one entry per ABS_MT_SLOT.
+  void HandleTouches(const std::vector<InProgressTouchEvdev>& touches,
+                     base::TimeDelta time);
+
+  // Returns whether the in-progress touch at ABS_MT_SLOT |slot| is noise.
+  bool SlotHasNoise(size_t slot) const;
+
+ private:
+  // Records how frequently noisy touches occur to UMA.
+  void RecordUMA(bool had_noise, base::TimeDelta time);
+
+  friend class TouchEventConverterEvdevTouchNoiseTest;
+
+  // The slots which are noise.
+  std::bitset<kNumTouchEvdevSlots> slots_with_noise_;
+
+  // The time of the previous noise occurence in any of the slots.
+  base::TimeDelta last_noise_time_;
+
+  std::vector<TouchNoiseFilter*> filters_;
+
+  DISALLOW_COPY_AND_ASSIGN(TouchNoiseFinder);
+};
+
+}  // namespace ui
+
+#endif  // UI_EVENTS_OZONE_EVDEV_TOUCH_NOISE_TOUCH_NOISE_FINDER_H_