Port Chromium OS touch noise filtering to Chromium

ui/events/ozone/evdev/touch_noise/touch_noise_finder.cc

+// 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.
+
+#include "ui/events/ozone/evdev/touch_noise/touch_noise_finder.h"
+
+#include "base/stl_util.h"
+#include "ui/events/ozone/evdev/touch_noise/far_apart_taps_touch_noise_filter.h"
+#include "ui/events/ozone/evdev/touch_noise/horizontally_aligned_touch_noise_filter.h"
+#include "ui/events/ozone/evdev/touch_noise/single_position_touch_noise_filter.h"
+#include "ui/events/ozone/evdev/touch_noise/touch_noise_filter.h"
+
+namespace ui {
+
+TouchNoiseFinder::TouchNoiseFinder() {
+  filters_.push_back(new FarApartTapsTouchNoiseFilter);
+  filters_.push_back(new HorizontallyAlignedTouchNoiseFilter);
+  filters_.push_back(new SinglePositionTouchNoiseFilter);
+}
+
+TouchNoiseFinder::~TouchNoiseFinder() {
+  STLDeleteElements(&filters_);
+}
+
+void TouchNoiseFinder::HandleTouches(
+    const std::vector<InProgressTouchEvdev>& touches,
+    base::TimeDelta time) {
+  for (const InProgressTouchEvdev& touch : touches) {
+    if (slots_with_noise_.test(touch.slot) && touch.type == ET_TOUCH_PRESSED)

[flackr, 2015/03/13 15:08:36]

Testing that it's true before setting it false is unnecessary, isn't it?

[pkotwicz, 2015/03/17 01:41:26]

Yes. I was doing this because reads are typically faster than writes, but that's
probably an overoptimization

+      slots_with_noise_.set(touch.slot, false);
+  }
+
+  for (TouchNoiseFilter* filter : filters_)
+    filter->Filter(touches, time, &slots_with_noise_);
+}
+
+bool TouchNoiseFinder::SlotHasNoise(size_t slot) const {
+  return slots_with_noise_.test(slot);
+}
+
+}  // namespace ui