Port Chromium OS touch noise filtering to Chromium

ui/events/ozone/evdev/touch_noise/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_TOUCH_NOISE_FILTER_H_
+#define UI_EVENTS_OZONE_EVDEV_TOUCH_NOISE_TOUCH_NOISE_FILTER_H_
+
+#include "base/time/time.h"
+#include "ui/gfx/geometry/point_f.h"
+
+namespace ui {
+
+class TouchNoiseFilter {
+ public:
+  static const int kNumSlots = 64;

[flackr, 2015/03/10 05:23:40]

Should probably use the same number of slots as in EventDeviceInfo:
https://code.google.com/p/chromium/codesearch#chromium/src/ui/events/ozone/ev...

[pkotwicz, 2015/03/13 03:53:16]

I have made the code use the same number of slots as TouchEventConverterEvdev
EVDEV_ABS_MT_COUNT is the number of multi-touch evdev bits (e.g.
ABS_MT_TOUCH_MAJOR) not the number of slots.

+
+  struct Finger {
+    Finger() : tracking_id(-1), canceled(false) {}
+    ~Finger() {}
+
+    gfx::PointF location;
+    int tracking_id;
+    bool canceled;
+  };
+
+  struct Frame {
+    base::TimeDelta timestamp;
+    Finger fingers[kNumSlots];
+  };
+
+  virtual ~TouchNoiseFilter() {}
+  virtual void FilterFrame(Frame* previous, Frame* current) = 0;
+};
+
+}  // namespace ui
+
+#endif  // UI_EVENTS_OZONE_EVDEV_TOUCH_NOISE_TOUCH_NOISE_FILTER_H_