Don't pass touches to gesture recognizer for async acks.

ui/events/gestures/gesture_recognizer_impl_mac.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 "base/macros.h"
 #include "ui/events/gestures/gesture_recognizer.h"
 
 namespace ui {
 
 namespace {
 
 // Stub implementation of GestureRecognizer for Mac. Currently only serves to
 // provide a no-op implementation of TransferEventsTo().
 class GestureRecognizerImplMac : public GestureRecognizer {
  public:
   GestureRecognizerImplMac() {}
   ~GestureRecognizerImplMac() override {}
 
  private:
   bool ProcessTouchEventPreDispatch(TouchEvent* event,
                                     GestureConsumer* consumer) override {
     return false;
   }
 
-  Gestures* AckAsyncTouchEvent(const TouchEvent& event,
-                               ui::EventResult result,
+  Gestures* AckAsyncTouchEvent(ui::EventResult result,
                                GestureConsumer* consumer) override {
     return NULL;
   }
   Gestures* AckSyncTouchEvent(const uint64 unique_event_id,
                               ui::EventResult result,
                               GestureConsumer* consumer) override {
     return NULL;
   }
   bool CleanupStateForConsumer(GestureConsumer* consumer) override {
     return false;
@@ skipping 24 matching lines @@
 
 }  // namespace
 
 // static
 GestureRecognizer* GestureRecognizer::Get() {
   CR_DEFINE_STATIC_LOCAL(GestureRecognizerImplMac, instance, ());
   return &instance;
 }
 
 }  // namespace ui