Introduce toHTMLIFrameElement

Source/core/rendering/RenderEmbeddedObject.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 2000 Simon Hausmann <hausmann@kde.org>
  *           (C) 2000 Stefan Schimanski (1Stein@gmx.de)
  * Copyright (C) 2004, 2005, 2006, 2008, 2009, 2010 Apple Inc. All rights reserved.
  *
  * 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.
@@ skipping 250 matching lines @@
 }
 
 void RenderEmbeddedObject::viewCleared()
 {
     // This is required for <object> elements whose contents are rendered by WebCore (e.g. src="foo.html").
     if (node() && widget() && widget()->isFrameView()) {
         FrameView* view = toFrameView(widget());
         int marginWidth = -1;
         int marginHeight = -1;
         if (node()->hasTagName(iframeTag)) {
-            HTMLIFrameElement* frame = static_cast<HTMLIFrameElement*>(node());
+            HTMLIFrameElement* frame = toHTMLIFrameElement(node());
             marginWidth = frame->marginWidth();
             marginHeight = frame->marginHeight();
         }
         if (marginWidth != -1)
             view->setMarginWidth(marginWidth);
         if (marginHeight != -1)
             view->setMarginHeight(marginHeight);
     }
 }
 
 bool RenderEmbeddedObject::scroll(ScrollDirection direction, ScrollGranularity granularity, float, Node**)
 {
     return false;
 }
 
 bool RenderEmbeddedObject::logicalScroll(ScrollLogicalDirection direction, ScrollGranularity granularity, float multiplier, Node** stopNode)
 {
     return false;
 }
 
 bool RenderEmbeddedObject::canHaveChildren() const
 {
     return false;
 }
 
 }