Eager Gesture Recognition on Aura

ui/events/gestures/gesture_provider_aura.cc

 // Copyright 2014 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/gestures/gesture_provider_aura.h"
 
 #include "base/auto_reset.h"
 #include "base/logging.h"
 #include "ui/events/event.h"
 #include "ui/events/gesture_detection/gesture_config_helper.h"
@@ skipping 10 matching lines @@
 }
 
 GestureProviderAura::~GestureProviderAura() {}
 
 bool GestureProviderAura::OnTouchEvent(const TouchEvent& event) {
   bool pointer_id_is_active = false;
   for (size_t i = 0; i < pointer_state_.GetPointerCount(); ++i) {
     if (event.touch_id() != pointer_state_.GetPointerId(i))
       continue;
     pointer_id_is_active = true;
+
+    // If this is a touchmove event, and it isn't different from the last
+    // event, ignore it.
+    if (event.type() == ET_TOUCH_MOVED &&
+        event.x() == pointer_state_.GetX(i) &&
+        event.y() == pointer_state_.GetY(i) &&
+        std::max(event.radius_x(), event.radius_y()) * 2 ==
+            pointer_state_.GetTouchMajor(i) &&
+        event.force() == pointer_state_.GetPressure(i)) {
+      return false;
+    }
     break;
   }
 
   if (event.type() == ET_TOUCH_PRESSED && pointer_id_is_active) {
     // Ignore touch press events if we already believe the pointer is down.
     return false;
   } else if (event.type() != ET_TOUCH_PRESSED && !pointer_id_is_active) {
     // We could have an active touch stream transfered to us, resulting in touch
     // move or touch up events without associated touch down events. Ignore
     // them.
@@ skipping 86 matching lines @@
 
   double double_tap_slop_square =
       GestureConfiguration::max_distance_between_taps_for_double_tap();
   double_tap_slop_square *= double_tap_slop_square;
   const float delta_x = previous_tap.x - current_tap.x;
   const float delta_y = previous_tap.y - current_tap.y;
   return (delta_x * delta_x + delta_y * delta_y < double_tap_slop_square);
 }
 
 }  // namespace content