v8binding: Implements an alternative of WindowProxy.[[DefineOwnProperty]].

third_party/WebKit/Source/core/frame/Window.idl

 /*
  * Copyright (C) 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 46 matching lines @@
     // other browsing contexts
     [Replaceable, CrossOrigin] readonly attribute Window frames;
     [Replaceable, CrossOrigin] readonly attribute unsigned long length;
     [Unforgeable, CrossOrigin] readonly attribute Window? top;
     // FIXME: opener should be of type any.
     [CrossOrigin, Custom=Setter] attribute Window opener;
     [Replaceable, CrossOrigin] readonly attribute Window? parent;
     [CheckSecurity=ReturnValue, Custom=Getter] readonly attribute Element? frameElement;
     // FIXME: open() should have 4 optional arguments with defaults.
     [Custom] Window? open(DOMString url, DOMString target, optional DOMString features);
-    // FIXME: These getters should not have [NotEnumerable].
+
+    // indexed properties
+    // https://html.spec.whatwg.org/C/browsers.html#windowproxy-getownproperty
     [NotEnumerable, CrossOrigin] getter Window (unsigned long index);
+    // https://html.spec.whatwg.org/C/browsers.html#windowproxy-defineownproperty
+    setter void (unsigned long index, any value);
+
+    // named properties
     [Custom, NotEnumerable, CrossOrigin] getter object (DOMString name);
 
     // the user agent
     [LogActivity=GetterOnly] readonly attribute Navigator navigator;
     [LogActivity=GetterOnly] readonly attribute ApplicationCache applicationCache;
 
     // user prompts
     [Measure, CallWith=ScriptState] void alert();
     [Measure, CallWith=ScriptState] void alert(DOMString message);
     [Measure, CallWith=ScriptState] boolean confirm(optional DOMString message = "");
@@ skipping 133 matching lines @@
 // FIXME: make this typedef accurate once enough of https://crbug.com/240176
 // is in place.
 // FIXME: consider putting this typedef in an .idl file containing spec-wide
 // utility type definitions.
 typedef MessagePort Transferable;
 
 Window implements GlobalEventHandlers;
 Window implements WindowBase64;
 Window implements WindowEventHandlers;
 Window implements WindowTimers;