Add palm suppression feature to EventConverterEvdev

ui/events/ozone/evdev/palm_suppression_filter.cc

Index: ui/events/ozone/evdev/palm_suppression_filter.cc
diff --git a/ui/events/ozone/evdev/palm_suppression_filter.cc b/ui/events/ozone/evdev/palm_suppression_filter.cc
new file mode 100644
index 0000000000000000000000000000000000000000..254f48abab10ea8b17253b65fde662ebda2c6a46
--- /dev/null
+++ b/ui/events/ozone/evdev/palm_suppression_filter.cc
@@ -0,0 +1,56 @@
+// 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.
+
+#include "ui/events/ozone/evdev/palm_suppression_filter.h"
+
+namespace ui {
+
+PalmSuppressionFilter::PalmSuppressionFilter(
+    DeviceEventDispatcherEvdev* dispatcher)
+    : dispatcher_(dispatcher) {}
+
+PalmSuppressionFilter::~PalmSuppressionFilter() {}
+
+bool PalmSuppressionFilter::FilterTouch(const TouchEventParams& params) {
+  DCHECK(touch_device_id_ == -1 || touch_device_id_ == params.device_id);
+  touch_device_id_ = params.device_id;
+
+  if (params.type == ET_TOUCH_PRESSED) {
+    reported_slots_.set(params.slot);
+  }
+
+  bool dispatch = !suppressing_ && reported_slots_[params.slot];
+
+  if (params.type == ET_TOUCH_RELEASED || params.type == ET_TOUCH_CANCELLED) {
+    reported_slots_.reset(params.slot);
+  }
+  return pass_through_ || dispatch;
+}
+
+void PalmSuppressionFilter::Reset() {
+  suppressing_ = false;
+  pass_through_ = true;
+  reported_slots_.reset();
+}
+
+void PalmSuppressionFilter::EnableSuppression(bool enabled,
+                                              base::TimeTicks timestamp) {
+  if (!suppressing_ && enabled)
+    CancelExistingTouches(timestamp);
+  suppressing_ = enabled;
+}
+
+void PalmSuppressionFilter::CancelExistingTouches(base::TimeTicks timestamp) {
+  for (size_t i = 0; i < reported_slots_.size(); ++i) {
+    if (reported_slots_[i]) {
+      dispatcher_->DispatchTouchEvent(
+          TouchEventParams(touch_device_id_, i, ET_TOUCH_CANCELLED,
+                           gfx::PointF(), ui::PointerDetails(), timestamp));
+    }
+  }
+  reported_slots_.reset();
+  pass_through_ = false;
+}
+
+}  // namespace ui