Don't refcount tracking id -> slot id mapping.

ui/events/cocoa/events_mac.mm

 // 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.
 
 #include "ui/events/event_utils.h"
 
 #include <Cocoa/Cocoa.h>
 
 #include "base/logging.h"
 #import "base/mac/mac_util.h"
@@ skipping 142 matching lines @@
 }
 
 base::NativeEvent CopyNativeEvent(const base::NativeEvent& event) {
   return [event copy];
 }
 
 void ReleaseCopiedNativeEvent(const base::NativeEvent& event) {
   [event release];
 }
 
-void IncrementTouchIdRefCount(const base::NativeEvent& native_event) {
-  NOTIMPLEMENTED();
-}
-
 void ClearTouchIdIfReleased(const base::NativeEvent& native_event) {
   NOTIMPLEMENTED();
 }
 
 int GetTouchId(const base::NativeEvent& native_event) {
   NOTIMPLEMENTED();
   return 0;
 }
 
 float GetTouchRadiusX(const base::NativeEvent& native_event) {
@@ skipping 88 matching lines @@
   uint16 return_value;
   [text getCharacters:&return_value];
   return return_value;
 }
 
 bool IsCharFromNative(const base::NativeEvent& native_event) {
   return false;
 }
 
 }  // namespace ui