Revert of Replace RenderFullScreen with top layer

Source/core/dom/Document.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2008, 2009, 2011, 2012 Google Inc. All rights reserved.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) Research In Motion Limited 2010-2011. All rights reserved.
@@ skipping 4757 matching lines @@
     if (!element->isInTopLayer())
         return;
     size_t position = m_topLayerElements.find(element);
     ASSERT(position != kNotFound);
     m_topLayerElements.remove(position);
     element->setIsInTopLayer(false);
 }
 
 HTMLDialogElement* Document::activeModalDialog() const
 {
-    Vector<RefPtr<Element> >::const_reverse_iterator end = m_topLayerElements.rend();
-    for (Vector<RefPtr<Element> >::const_reverse_iterator it = m_topLayerElements.rbegin(); it != end; ++it) {
-        if (!it->get()->hasTagName(dialogTag))
-            continue;
-        HTMLDialogElement* dialog = toHTMLDialogElement(it->get());
-        if (dialog->isModal())
-            return dialog;
-    }
-    return 0;
+    if (m_topLayerElements.isEmpty())
+        return 0;
+    return toHTMLDialogElement(m_topLayerElements.last().get());
 }
 
 void Document::webkitExitPointerLock()
 {
     if (!page())
         return;
     if (Element* target = page()->pointerLockController().element()) {
         if (target->document() != this)
             return;
     }
@@ skipping 504 matching lines @@
     if (!page->focusController().isActive() || !page->focusController().isFocused())
         return false;
     if (Frame* focusedFrame = page->focusController().focusedFrame()) {
         if (focusedFrame->tree().isDescendantOf(frame()))
             return true;
     }
     return false;
 }
 
 } // namespace WebCore