Introduce toHTMLIFrameElement

Source/core/css/resolver/StyleResolver.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 2004-2005 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2006, 2007 Nicholas Shanks (webkit@nickshanks.com)
  * Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Alexey Proskuryakov <ap@webkit.org>
  * Copyright (C) 2007, 2008 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (c) 2011, Code Aurora Forum. All rights reserved.
  * Copyright (C) Research In Motion Limited 2011. All rights reserved.
@@ skipping 1266 matching lines @@
     if (style->hasPseudoStyle(FIRST_LETTER))
         style->setUnique();
 
     // FIXME: when dropping the -webkit prefix on transform-style, we should also have opacity < 1 cause flattening.
     if (style->preserves3D() && (style->overflowX() != OVISIBLE
         || style->overflowY() != OVISIBLE
         || style->hasFilter()))
         style->setTransformStyle3D(TransformStyle3DFlat);
 
     // Seamless iframes behave like blocks. Map their display to inline-block when marked inline.
-    if (e && e->hasTagName(iframeTag) && style->display() == INLINE && static_cast<HTMLIFrameElement*>(e)->shouldDisplaySeamlessly())
+    if (e && e->hasTagName(iframeTag) && style->display() == INLINE && toHTMLIFrameElement(e)->shouldDisplaySeamlessly())
         style->setDisplay(INLINE_BLOCK);
 
     adjustGridItemPosition(style);
 
     if (e && e->isSVGElement()) {
         // Spec: http://www.w3.org/TR/SVG/masking.html#OverflowProperty
         if (style->overflowY() == OSCROLL)
             style->setOverflowY(OHIDDEN);
         else if (style->overflowY() == OAUTO)
             style->setOverflowY(OVISIBLE);
@@ skipping 640 matching lines @@
     info.addMember(m_state, "state");
 
     // FIXME: move this to a place where it would be called only once?
     info.addMember(CSSDefaultStyleSheets::defaultStyle, "defaultStyle");
     info.addMember(CSSDefaultStyleSheets::defaultQuirksStyle, "defaultQuirksStyle");
     info.addMember(CSSDefaultStyleSheets::defaultPrintStyle, "defaultPrintStyle");
     info.addMember(CSSDefaultStyleSheets::defaultViewSourceStyle, "defaultViewSourceStyle");
 }
 
 } // namespace WebCore