Remove old permission delegation prototype

third_party/WebKit/Source/core/html/HTMLIFrameElement.idl

 /*
  * Copyright (C) 2006, 2007, 2009, 2010 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 16 matching lines @@
     [CEReactions, PutForwards=value] readonly attribute DOMTokenList sandbox;
     // Note: The seamless attribute was once supported, but was removed.
     [CEReactions, Reflect] attribute boolean allowFullscreen;
     [CEReactions, Reflect] attribute DOMString width;
     [CEReactions, Reflect] attribute DOMString height;
 
     [CheckSecurity=ReturnValue] readonly attribute Document? contentDocument;
     readonly attribute Window? contentWindow;
     [CheckSecurity=ReturnValue, RaisesException] Document? getSVGDocument();
     [CEReactions, Reflect, ReflectOnly=("","no-referrer","origin","no-referrer-when-downgrade","origin-when-cross-origin","unsafe-url"), ReflectMissing="", ReflectInvalid=""] attribute DOMString referrerPolicy;
-    // https://noncombatant.github.io/permission-delegation-api/#delegation-via-the-declarative-api
-    [RuntimeEnabled=PermissionDelegation, PutForwards=value] readonly attribute DOMTokenList permissions;
     // https://w3c.github.io/webappsec-csp/embedded/#dom-htmliframeelement-csp
     [RuntimeEnabled=EmbedderCSPEnforcement, CEReactions, Reflect] attribute DOMString csp;
 
     // Feature Policy allow attribute
     // https://wicg.github.io/feature-policy/
     [RuntimeEnabled=FeaturePolicy, CEReactions, PutForwards=value] readonly attribute DOMTokenList allow;
     // obsolete members
     // https://html.spec.whatwg.org/#HTMLIFrameElement-partial
     [CEReactions, Reflect] attribute DOMString align;
     [CEReactions, Reflect] attribute DOMString scrolling;
     [CEReactions, Reflect] attribute DOMString frameBorder;
     [CEReactions, Reflect, URL] attribute DOMString longDesc;
 
     [CEReactions, Reflect, TreatNullAs=EmptyString] attribute DOMString marginHeight;
     [CEReactions, Reflect, TreatNullAs=EmptyString] attribute DOMString marginWidth;
 };