Introduce toHTMLInputElement(Node*), and use it.

Source/core/page/Chrome.cpp

 /*
  * Copyright (C) 2006, 2007, 2009, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2010 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) 2012, Samsung Electronics. 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 342 matching lines @@
     String toolTip = result.spellingToolTip(toolTipDirection);
 
     // Next we'll consider a tooltip for element with "title" attribute
     if (toolTip.isEmpty())
         toolTip = result.title(toolTipDirection);
 
     // Lastly, for <input type="file"> that allow multiple files, we'll consider a tooltip for the selected filenames
     if (toolTip.isEmpty()) {
         if (Node* node = result.innerNonSharedNode()) {
             if (node->hasTagName(inputTag)) {
-                HTMLInputElement* input = static_cast<HTMLInputElement*>(node);
+                HTMLInputElement* input = toHTMLInputElement(node);
                 toolTip = input->defaultToolTip();
 
                 // FIXME: We should obtain text direction of tooltip from
                 // ChromeClient or platform. As of October 2011, all client
                 // implementations don't use text direction information for
                 // ChromeClient::setToolTip. We'll work on tooltip text
                 // direction during bidi cleanup in form inputs.
                 toolTipDirection = LTR;
             }
         }
@@ skipping 80 matching lines @@
 }
 
 void Chrome::notifyPopupOpeningObservers() const
 {
     const Vector<PopupOpeningObserver*> observers(m_popupOpeningObservers);
     for (size_t i = 0; i < observers.size(); ++i)
         observers[i]->willOpenPopup();
 }
 
 } // namespace WebCore