MacViews: Send Mac scrollWheel NSEvents as ui::ET_SCROLL (ui::ScrollEvent).

ui/events/event.h

 // 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.
 
 #ifndef UI_EVENTS_EVENT_H_
 #define UI_EVENTS_EVENT_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 956 matching lines @@
   // Scale the scroll event's offset value.
   // This is useful in the multi-monitor setup where it needs to be scaled
   // to provide a consistent user experience.
   void Scale(const float factor);
 
   float x_offset() const { return x_offset_; }
   float y_offset() const { return y_offset_; }
   float x_offset_ordinal() const { return x_offset_ordinal_; }
   float y_offset_ordinal() const { return y_offset_ordinal_; }
   int finger_count() const { return finger_count_; }
+  EventMomentumPhase momentum_phase() const { return momentum_phase_; }
 
  private:
   // Potential accelerated offsets.
   float x_offset_;
   float y_offset_;
   // Unaccelerated offsets.
   float x_offset_ordinal_;
   float y_offset_ordinal_;
   // Number of fingers on the pad.
   int finger_count_;
+
+  // For non-fling events, provides momentum information (e.g. for the case
+  // where the device provides continuous event updates during a fling).
+  EventMomentumPhase momentum_phase_;
 };
 
 class EVENTS_EXPORT GestureEvent : public LocatedEvent {
  public:
     // The constructor takes a default unique_touch_id of zero to support many
     // (80+) existing tests that doesn't care about this id.
   GestureEvent(float x,
                float y,
                int flags,
                base::TimeTicks time_stamp,
@@ skipping 24 matching lines @@
   // dispatched. This field gets a non-zero value only for gestures that are
   // released through TouchDispositionGestureFilter::SendGesture. The gesture
   // events that aren't fired directly in response to processing a touch-event
   // (e.g. timer fired ones), this id is zero. See crbug.com/618738.
   uint32_t unique_touch_event_id_;
 };
 
 }  // namespace ui
 
 #endif  // UI_EVENTS_EVENT_H_