Clean up forward declarations in Source/modules

Source/modules/webdatabase/SQLStatementBackend.h

 /*
  * Copyright (C) 2007, 2013 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 12 matching lines @@
  * 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 SQLStatementBackend_h
 #define SQLStatementBackend_h
 
 #include "modules/webdatabase/sqlite/SQLValue.h"
 #include "platform/heap/Handle.h"
-#include "wtf/Forward.h"
 #include "wtf/Vector.h"
-#include "wtf/text/WTFString.h"
 
 namespace blink {
 
 class Database;
 class SQLErrorData;
 class SQLResultSet;
 class SQLStatement;
-class SQLTransactionBackend;
 
 class SQLStatementBackend final : public GarbageCollectedFinalized<SQLStatementBackend> {
 public:
     static SQLStatementBackend* create(SQLStatement*,
         const String& sqlStatement, const Vector<SQLValue>& arguments, int permissions);
     void trace(Visitor*);
 
     bool execute(Database*);
     bool lastExecutionFailedDueToQuota() const;
 
@@ skipping 20 matching lines @@
 
     OwnPtr<SQLErrorData> m_error;
     Member<SQLResultSet> m_resultSet;
 
     int m_permissions;
 };
 
 } // namespace blink
 
 #endif // SQLStatementBackend_h