ui: Remove some unnecessary functions from the API.

ui/events/ozone/events_ozone.cc

Index: ui/events/ozone/events_ozone.cc
diff --git a/ui/events/ozone/events_ozone.cc b/ui/events/ozone/events_ozone.cc
index 7d3f627d0788abf8793fd4621ce30d1640d65f1b..9ab835c1ff839ab20aca211466906acb7980d5da 100644
--- a/ui/events/ozone/events_ozone.cc
+++ b/ui/events/ozone/events_ozone.cc
@@ -144,15 +144,6 @@ bool GetGestureTimes(const base::NativeEvent& native_event,
   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;