Manage WebSQL callbacks with OwnPtr instead of refcounting

Source/modules/webdatabase/SQLStatementErrorCallback.h

 /*
  * Copyright (C) 2007 Apple 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:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 11 matching lines @@
  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #ifndef SQLStatementErrorCallback_h
 #define SQLStatementErrorCallback_h
 
-#include "wtf/ThreadSafeRefCounted.h"
-
 namespace WebCore {
 
 class SQLTransaction;
 class SQLError;
 
-class SQLStatementErrorCallback : public ThreadSafeRefCounted<SQLStatementErrorCallback> {
+class SQLStatementErrorCallback {
 public:
     virtual ~SQLStatementErrorCallback() { }
     virtual bool handleEvent(SQLTransaction*, SQLError*) = 0;
 };
 
 }
 
 #endif // SQLStatementErrorCallback_h