Introduce toHTMLInputElement(Node*), and use it.

Source/core/page/EventHandler.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2012 Digia Plc. and/or its subsidiary(-ies)
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
@@ skipping 1029 matching lines @@
 
     Widget* widget = toRenderWidget(renderer)->widget();
     if (!widget || !widget->isFrameView())
         return 0;
 
     return toFrameView(widget)->frame();
 }
 
 static bool isSubmitImage(Node* node)
 {
-    return node && node->hasTagName(inputTag) && static_cast<HTMLInputElement*>(node)->isImageButton();
+    return node && node->hasTagName(inputTag) && toHTMLInputElement(node)->isImageButton();
 }
 
 // Returns true if the node's editable block is not current focused for editing
 static bool nodeIsNotBeingEdited(Node* node, Frame* frame)
 {
     return frame->selection()->rootEditableElement() != node->rootEditableElement();
 }
 
 bool EventHandler::useHandCursor(Node* node, bool isOverLink, bool shiftKey)
 {
@@ skipping 2816 matching lines @@
 unsigned EventHandler::accessKeyModifiers()
 {
 #if OS(DARWIN)
     return PlatformEvent::CtrlKey | PlatformEvent::AltKey;
 #else
     return PlatformEvent::AltKey;
 #endif
 }
 
 } // namespace WebCore