Move UIEvent.pageX/pageY/layerX/layerY to MouseEvent

Source/core/events/UIEvent.idl

 /*
  * Copyright (C) 2006 Apple Computer, Inc.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 16 matching lines @@
     [RuntimeEnabled=InputDevice] readonly attribute InputDevice? sourceDevice;
 
     // https://w3c.github.io/uievents/#idl-interface-UIEvent-initializers
     // TODO(philipj): None of the initUIEvent() arguments should be optional.
     void initUIEvent([Default=Undefined] optional DOMString type,
                                     [Default=Undefined] optional boolean bubbles,
                                     [Default=Undefined] optional boolean cancelable,
                                     [Default=Undefined] optional Window? view,
                                     [Default=Undefined] optional long detail);
 
-    // Non-standard
-    [MeasureAs=UIEventLayerX] readonly attribute long layerX;
-    [MeasureAs=UIEventLayerY] readonly attribute long layerY;
-    [MeasureAs=UIEventPageX] readonly attribute long pageX;
-    [MeasureAs=UIEventPageY] readonly attribute long pageY;
-
     // FIXME: these belong on the KeyboardEvent interface
     [MeasureAs=UIEventCharCode] readonly attribute long charCode;
     [MeasureAs=UIEventKeyCode] readonly attribute long keyCode;
     [MeasureAs=UIEventWhich] readonly attribute long which;
 };