Indicate whether a touch event will cause scrolling

ui/events/gestures/gesture_recognizer_impl.cc

 // Copyright (c) 2012 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_recognizer_impl.h"
 
 #include <limits>
 
 #include "base/command_line.h"
 #include "base/logging.h"
@@ skipping 218 matching lines @@
 void GestureRecognizerImpl::DispatchGestureEvent(GestureEvent* event) {
   GestureConsumer* consumer = GetTargetForGestureEvent(*event);
   if (consumer) {
     GestureEventHelper* helper = FindDispatchHelperForConsumer(consumer);
     if (helper)
       helper->DispatchGestureEvent(event);
   }
 }
 
 bool GestureRecognizerImpl::ProcessTouchEventPreDispatch(
-    const TouchEvent& event,
+    TouchEvent* event,
     GestureConsumer* consumer) {
-  SetupTargets(event, consumer);
+  SetupTargets(*event, consumer);
 
-  if (event.result() & ER_CONSUMED)
+  if (event->result() & ER_CONSUMED)
     return false;
 
   GestureProviderAura* gesture_provider =
       GetGestureProviderForConsumer(consumer);
   return gesture_provider->OnTouchEvent(event);
 }
 
 GestureRecognizer::Gestures*
 GestureRecognizerImpl::ProcessTouchEventPostDispatch(
     const TouchEvent& event,
@@ skipping 86 matching lines @@
   std::vector<GestureEventHelper*>::iterator it;
   for (it = helpers.begin(); it != helpers.end(); ++it)
     gesture_recognizer->AddGestureEventHelper(*it);
 
   helpers.clear();
   g_gesture_recognizer_instance =
       static_cast<GestureRecognizerImpl*>(gesture_recognizer);
 }
 
 }  // namespace ui