Remove unused function on HTMLImportsController.

Source/core/html/imports/HTMLImportsController.h

 /*
  * Copyright (C) 2013 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 47 matching lines @@
 
     explicit HTMLImportsController(Document&);
     virtual ~HTMLImportsController();
 
     HTMLImportTreeRoot* root() const { return m_root.get(); }
 
     bool shouldBlockScriptExecution(const Document&) const;
     void wasDetachedFrom(const Document&);
 
     HTMLImportChild* load(HTMLImport* parent, HTMLImportChildClient*, FetchRequest);
-    void showSecurityErrorMessage(const String&);
 
     Document* master() const;
 
     HTMLImportLoader* createLoader();
 
     size_t loaderCount() const { return m_loaders.size(); }
     HTMLImportLoader* loaderAt(size_t i) const { return m_loaders[i].get(); }
     HTMLImportLoader* loaderFor(const Document&) const;
 
 private:
     HTMLImportChild* createChild(const KURL&, HTMLImportLoader*, HTMLImport* parent, HTMLImportChildClient*);
     void clear();
 
     OwnPtr<HTMLImportTreeRoot> m_root;
 
     typedef Vector<RefPtr<HTMLImportLoader> > LoaderList;
     LoaderList m_loaders;
 };
 
 } // namespace WebCore
 
 #endif // HTMLImportsController_h