Update WebKit IDLs after chrome roll.

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,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Library General Public License for more details.
  *
  * You should have received a copy of the GNU Library General Public License
  * along with this library; see the file COPYING.LIB.  If not, write to
  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  */
 
 interface HTMLIFrameElement : HTMLElement {
     [Reflect] attribute DOMString align;
     [Reflect] attribute DOMString frameBorder;
     [Reflect] attribute DOMString height;
     [Reflect] attribute DOMString longDesc;
     [Reflect] attribute DOMString marginHeight;
     [Reflect] attribute DOMString marginWidth;
     [Reflect] attribute DOMString name;
     [Reflect] attribute DOMString sandbox;
-    [Reflect, Conditional=IFRAME_SEAMLESS] attribute boolean seamless;
+    [Reflect, V8EnabledAtRuntime=seamlessIFrames] attribute boolean seamless;
     [Reflect] attribute DOMString scrolling;
     [Reflect, URL] attribute DOMString src;
     [Reflect] attribute DOMString srcdoc;
     [Reflect] attribute DOMString width;
 
     // Introduced in DOM Level 2:
     [CheckSecurityForNode] readonly attribute Document contentDocument;
 
     // Extensions
     readonly attribute DOMWindow contentWindow;
 
 #if defined(ENABLE_SVG) && ENABLE_SVG
 #if !defined(LANGUAGE_OBJECTIVE_C) || !LANGUAGE_OBJECTIVE_C || defined(ENABLE_SVG_DOM_OBJC_BINDINGS) && ENABLE_SVG_DOM_OBJC_BINDINGS
     [CheckSecurityForNode] SVGDocument getSVGDocument()
         raises(DOMException);
 #endif
 #endif
 };