ui: Remove some unnecessary functions from the API.

ui/events/ozone/events_ozone.cc

 // Copyright (c) 2013 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/event.h"
 #include "ui/events/event_constants.h"
 #include "ui/events/event_utils.h"
 
 namespace ui {
 
@@ skipping 126 matching lines @@
 }
 
 bool GetGestureTimes(const base::NativeEvent& native_event,
                      double* start_time,
                      double* end_time) {
   *start_time = 0;
   *end_time = 0;
   return false;
 }
 
-void SetNaturalScroll(bool /* enabled */) { NOTIMPLEMENTED(); }
-
-bool IsNaturalScrollEnabled() { return false; }
-
-bool IsTouchpadEvent(const base::NativeEvent& event) {
-  NOTIMPLEMENTED();
-  return false;
-}
-
 int GetModifiersFromKeyState() {
   NOTIMPLEMENTED();
   return 0;
 }
 
 }  // namespace ui