Drag and drop cleans up touch sequences from the source window.

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 <utility>
 
 #include "base/auto_reset.h"
 #include "base/logging.h"
 #include "ui/events/event.h"
+#include "ui/events/event_utils.h"
 #include "ui/events/gesture_detection/gesture_configuration.h"
 #include "ui/events/gesture_detection/gesture_event_data.h"
 #include "ui/events/gesture_detection/gesture_provider_config_helper.h"
 
 namespace ui {
 
 GestureProviderAura::GestureProviderAura(GestureConsumer* consumer,
                                          GestureProviderAuraClient* client)
     : client_(client),
       filtered_gesture_provider_(
@@ skipping 45 matching lines @@
 ScopedVector<GestureEvent>* GestureProviderAura::GetAndResetPendingGestures() {
   if (pending_gestures_.empty())
     return NULL;
   // Caller is responsible for deleting old_pending_gestures.
   ScopedVector<GestureEvent>* old_pending_gestures =
       new ScopedVector<GestureEvent>();
   old_pending_gestures->swap(pending_gestures_);
   return old_pending_gestures;
 }
 
+void GestureProviderAura::OnTouchEnter(int pointer_id, float x, float y) {
+  std::unique_ptr<TouchEvent> touch_event(new TouchEvent(
+      ET_TOUCH_PRESSED, gfx::Point(), EF_IS_SYNTHESIZED, pointer_id,
+      ui::EventTimeForNow(), 0.0f, 0.0f, 0.0f, 0.0f));
+  gfx::PointF point(x, y);
+  touch_event->set_location_f(point);
+  touch_event->set_root_location_f(point);
+
+  OnTouchEvent(touch_event.get());
+  OnTouchEventAck(touch_event->unique_event_id(), true);
+}
+
 }  // namespace content