Add ShadowRootInit dictionary.

Source/core/dom/Element.idl

 /*
  * Copyright (C) 2006, 2007, 2009 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 @@
     HTMLCollection getElementsByClassName(DOMString classNames);
 
     // DOM Parsing and Serialization
     // https://dvcs.w3.org/hg/innerhtml/raw-file/tip/index.html#extensions-to-the-element-interface
     [TreatNullAs=NullString, CustomElementCallbacks, RaisesException=Setter, ExposeJSAccessors] attribute DOMString innerHTML;
     [TreatNullAs=NullString, CustomElementCallbacks, RaisesException=Setter] attribute DOMString outerHTML;
     [CustomElementCallbacks, RaisesException, MeasureAs=InsertAdjacentHTML] void insertAdjacentHTML(DOMString position, DOMString text);
 
     // Shadow DOM
     // http://w3c.github.io/webcomponents/spec/shadow/#extensions-to-element-interface
-    [RaisesException, CallWith=ScriptState, MeasureAs=ElementCreateShadowRoot] ShadowRoot createShadowRoot();
+    [RaisesException, CallWith=ScriptState, MeasureAs=ElementCreateShadowRoot] ShadowRoot createShadowRoot(optional ShadowRootInit shadowRootInitDict);

[hayato, 2015/06/03 08:46:12]

We have to implement this feature as Runtime-Enabled feature. We can't expose
this feature yet.

Also we have to measure the usage of createShadowRoot() and
createShadowRoot(dict) separately so that we can deprecate parameterless
createShadowRoot() in the future.

     NodeList getDestinationInsertionPoints();
     [PerWorldBindings] readonly attribute ShadowRoot? shadowRoot;
 
     // Pointer Lock
     // https://dvcs.w3.org/hg/pointerlock/raw-file/default/index.html#extensions-to-the-element-interface
     [MeasureAs=ElementRequestPointerLock] void requestPointerLock();
 
     // CSSOM View Module
     // http://dev.w3.org/csswg/cssom-view/#extension-to-the-element-interface
     // FIXME: getClientRect() and getBoundingClientRect() should
@@ skipping 63 matching lines @@
     [RuntimeEnabled=Touch] attribute EventHandler ontouchcancel;
     [RuntimeEnabled=Touch] attribute EventHandler ontouchend;
     [RuntimeEnabled=Touch] attribute EventHandler ontouchmove;
     [RuntimeEnabled=Touch] attribute EventHandler ontouchstart;
     attribute EventHandler onwheel;
 };
 
 Element implements ParentNode;
 Element implements ChildNode;
 Element implements NonDocumentTypeChildNode;