Remove ENABLE(FILE_SYSTEM) compile-time flag.

Source/WebCore/Modules/filesystem/FileWriterBase.h

 /*
  * Copyright (C) 2010 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 13 matching lines @@
  * 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 FileWriterBase_h
 #define FileWriterBase_h
 
-#if ENABLE(FILE_SYSTEM)
-
 #include <wtf/OwnPtr.h>
 #include <wtf/PassOwnPtr.h>
 #include <wtf/RefCounted.h>
 
 namespace WebCore {
 
 class AsyncFileWriter;
 
 typedef int ExceptionCode;
 
@@ skipping 34 matching lines @@
 private:
     friend class WTF::RefCounted<FileWriterBase>;
 
     OwnPtr<AsyncFileWriter> m_writer;
     long long m_position;
     long long m_length;
 };
 
 } // namespace WebCore
 
-#endif // ENABLE(FILE_SYSTEM)
-
 #endif // FileWriterBase_h