Introduce toHTMLInputElement(Node*), and use it.

Source/WebKit/chromium/src/WebSearchableFormData.cpp

 /*
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 120 matching lines @@
     return !initialSelected || initialSelected->selected();
 }
 
 // Returns true if the form element is in its default state, false otherwise.
 // The default state is the state of the form element on initial load of the
 // page, and varies depending upon the form element. For example, a checkbox is
 // in its default state if the checked state matches the state of the checked attribute.
 bool IsInDefaultState(HTMLFormControlElement* formElement)
 {
     if (formElement->hasTagName(HTMLNames::inputTag)) {
-        const HTMLInputElement* inputElement = static_cast<HTMLInputElement*>(formElement);
+        const HTMLInputElement* inputElement = toHTMLInputElement(formElement);
         if (inputElement->isCheckbox() || inputElement->isRadioButton())
             return inputElement->checked() == inputElement->hasAttribute(checkedAttr);
     } else if (formElement->hasTagName(HTMLNames::selectTag))
         return IsSelectInDefaultState(static_cast<HTMLSelectElement*>(formElement));
     return true;
 }
 
 // Look for a suitable search text field in a given HTMLFormElement 
 // Return nothing if one of those items are found:
 //  - A text area field
@@ skipping 22 matching lines @@
             // Return nothing if a file upload field or a password field are found.
             if (input->isFileUpload() || input->isPasswordField())
                 return 0;
 
             if (input->isTextField()) {
                 if (textElement) {
                     // The auto-complete bar only knows how to fill in one value.
                     // This form has multiple fields; don't treat it as searchable.
                     return 0;
                 }
-                textElement = static_cast<HTMLInputElement*>(formElement);
+                textElement = toHTMLInputElement(formElement);
             }
         }
     }
     return textElement;
 }
 
 // Build a search string based on a given HTMLFormElement and HTMLInputElement
 // 
 // Search string output example from www.google.com:
 // "hl=en&source=hp&biw=1085&bih=854&q={searchTerms}&btnG=Google+Search&aq=f&aqi=&aql=&oq="
@@ skipping 93 matching lines @@
 
     String action(formElement->action());
     KURL url(formElement->document()->completeURL(action.isNull() ? "" : action));
     RefPtr<FormData> formData = FormData::create(encodedString);
     url.setQuery(formData->flattenToString());
     m_url = url;
     m_encoding = String(encoding.name()); 
 }
 
 } // namespace WebKit