Indicate whether a touch event will cause scrolling

ui/events/gestures/gesture_provider_aura.h

 // 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.
 
 #ifndef UI_EVENTS_GESTURE_DETECTION_UI_GESTURE_PROVIDER_H_
 #define UI_EVENTS_GESTURE_DETECTION_UI_GESTURE_PROVIDER_H_
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_vector.h"
 #include "ui/events/event.h"
@@ skipping 11 matching lines @@
   virtual void OnGestureEvent(GestureEvent* event) = 0;
 };
 
 // Provides gesture detection and dispatch given a sequence of touch events
 // and touch event acks.
 class EVENTS_EXPORT GestureProviderAura : public GestureProviderClient {
  public:
   GestureProviderAura(GestureProviderAuraClient* client);
   ~GestureProviderAura() override;
 
-  bool OnTouchEvent(const TouchEvent& event);
+  bool OnTouchEvent(TouchEvent* event);
   void OnTouchEventAck(bool event_consumed);
   const MotionEventAura& pointer_state() { return pointer_state_; }
   ScopedVector<GestureEvent>* GetAndResetPendingGestures();
 
   // GestureProviderClient implementation
   void OnGestureEvent(const GestureEventData& gesture) override;
 
  private:
   bool IsConsideredDoubleTap(const GestureEventData& previous_tap,
                              const GestureEventData& current_tap) const;
 
   scoped_ptr<GestureEventData> previous_tap_;
 
   GestureProviderAuraClient* client_;
   MotionEventAura pointer_state_;
   FilteredGestureProvider filtered_gesture_provider_;
 
   ui::LatencyInfo last_touch_event_latency_info_;
   bool handling_event_;
   ScopedVector<GestureEvent> pending_gestures_;
 
   DISALLOW_COPY_AND_ASSIGN(GestureProviderAura);
 };
 
 }  // namespace ui
 
 #endif  // UI_EVENTS_GESTURE_DETECTION_UI_GESTURE_PROVIDER_H_