Introduce isHTMLTitleElement and toHTMLTitleElement

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 1305 matching lines @@
         if (HTMLElement* headElement = head()) {
             m_titleElement = createElement(titleTag, false);
             headElement->appendChild(m_titleElement, ASSERT_NO_EXCEPTION);
         }
     }
 
     // The DOM API has no method of specifying direction, so assume LTR.
     updateTitle(StringWithDirection(title, LTR));
 
     if (m_titleElement) {
-        ASSERT(m_titleElement->hasTagName(titleTag));
-        if (m_titleElement->hasTagName(titleTag))
-            static_cast<HTMLTitleElement*>(m_titleElement.get())->setText(title);
+        ASSERT(isHTMLTitleElement(m_titleElement.get()));
+        if (isHTMLTitleElement(m_titleElement.get()))
+            toHTMLTitleElement(m_titleElement.get())->setText(title);
     }
 }
 
 void Document::setTitleElement(const StringWithDirection& title, Element* titleElement)
 {
     if (titleElement != m_titleElement) {
         if (m_titleElement || m_titleSetExplicitly)
             // Only allow the first title element to change the title -- others have no effect.
             return;
         m_titleElement = titleElement;
     }
 
     updateTitle(title);
 }
 
 void Document::removeTitle(Element* titleElement)
 {
     if (m_titleElement != titleElement)
         return;
 
     m_titleElement = 0;
     m_titleSetExplicitly = false;
 
     // Update title based on first title element in the head, if one exists.
     if (HTMLElement* headElement = head()) {
-        for (Node* e = headElement->firstChild(); e; e = e->nextSibling())
-            if (e->hasTagName(titleTag)) {
-                HTMLTitleElement* titleElement = static_cast<HTMLTitleElement*>(e);
+        for (Node* e = headElement->firstChild(); e; e = e->nextSibling()) {
+            if (isHTMLTitleElement(e)) {
+                HTMLTitleElement* titleElement = toHTMLTitleElement(e);
                 setTitleElement(titleElement->textWithDirection(), titleElement);
                 break;
             }
+        }
     }
 
     if (!m_titleElement)
         updateTitle(StringWithDirection());
 }
 
 PageVisibilityState Document::visibilityState() const
 {
     // The visibility of the document is inherited from the visibility of the
     // page. If there is no page associated with the document, we will assume
@@ skipping 3771 matching lines @@
 {
     return DocumentLifecycleNotifier::create(this);
 }
 
 DocumentLifecycleNotifier* Document::lifecycleNotifier()
 {
     return static_cast<DocumentLifecycleNotifier*>(ScriptExecutionContext::lifecycleNotifier());
 }
 
 } // namespace WebCore