Get rid of unnecessary forward declarations in components/autofill/

components/autofill/content/renderer/form_cache.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef COMPONENTS_AUTOFILL_CONTENT_RENDERER_FORM_CACHE_H_
 #define COMPONENTS_AUTOFILL_CONTENT_RENDERER_FORM_CACHE_H_
 
 #include <map>
 #include <set>
 #include <vector>
 
 #include "base/strings/string16.h"
 
 namespace blink {
 class WebDocument;
 class WebFormControlElement;
-class WebFormElement;
 class WebFrame;
 class WebInputElement;
 class WebSelectElement;
 }
 
 namespace autofill {
 
 struct FormData;
 struct FormDataPredictions;
 
@@ skipping 34 matching lines @@
 
   // The cached initial values for checkable <input> elements.
   std::map<const blink::WebInputElement, bool> initial_checked_state_;
 
   DISALLOW_COPY_AND_ASSIGN(FormCache);
 };
 
 }  // namespace autofill
 
 #endif  // COMPONENTS_AUTOFILL_CONTENT_RENDERER_FORM_CACHE_H_