Add deepPath

third_party/WebKit/Source/core/events/Event.idl

 /*
  * Copyright (C) 2006, 2007, 2009, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2006 Samuel Weinig <sam.weinig@gmail.com>
  *
  * 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,
@@ skipping 46 matching lines @@
     [CallWith=ScriptState] readonly attribute DOMHighResTimeStamp timeStamp;
 
     // FIXME: initEvent()'s arguments should not be optional.
     [Measure] void initEvent([Default=Undefined] optional DOMString type,
                              [Default=Undefined] optional boolean bubbles,
                              [Default=Undefined] optional boolean cancelable);
 
     // Shadow DOM
     // https://w3c.github.io/webcomponents/spec/shadow/#extensions-to-event-interface
     [MeasureAs=EventPath, CallWith=ScriptState] readonly attribute EventTarget[] path;
-
+    [RuntimeEnabled=ShadowDOMV1, ImplementedAs=path, MeasureAs=EventDeepPath, CallWith=ScriptState] readonly attribute EventTarget[] deepPath;
     // Non-standard APIs
     const unsigned short MOUSEDOWN = 1;
     const unsigned short MOUSEUP   = 2;
     const unsigned short MOUSEOVER = 4;
     const unsigned short MOUSEOUT  = 8;
     const unsigned short MOUSEMOVE = 16;
     const unsigned short MOUSEDRAG = 32;
     const unsigned short CLICK     = 64;
     const unsigned short DBLCLICK  = 128;
     const unsigned short KEYDOWN   = 256;
     const unsigned short KEYUP     = 512;
     const unsigned short KEYPRESS  = 1024;
     const unsigned short DRAGDROP  = 2048;
     const unsigned short FOCUS     = 4096;
     const unsigned short BLUR      = 8192;
     const unsigned short SELECT    = 16384;
     const unsigned short CHANGE    = 32768;
     [MeasureAs=EventSrcElement] readonly attribute EventTarget srcElement;
     [MeasureAs=EventReturnValue, CallWith=ExecutionContext, ImplementedAs=legacyReturnValue] attribute boolean returnValue;
     [MeasureAs=EventCancelBubble] attribute boolean cancelBubble;
 };