[NaCl SDK] Add nacl_io and sdk_util namespaces.

native_client_sdk/src/libraries/nacl_io/mount_factory.h

 /* Copyright (c) 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 LIBRARIES_NACL_IO_MOUNT_FACTORY_H_
 #define LIBRARIES_NACL_IO_MOUNT_FACTORY_H_
 
 #include <map>
 #include <string>
 
 #include "nacl_io/error.h"
 #include "sdk_util/scoped_ref.h"
 
+namespace nacl_io {
+
 class PepperInterface;
 class Mount;
 
 typedef std::map<std::string, std::string> StringMap_t;
 
 class MountFactory {
  public:
   virtual ~MountFactory() {}
   virtual Error CreateMount(int dev,
                             StringMap_t& args,
                             PepperInterface* ppapi,
-                            ScopedRef<Mount>* out_mount) = 0;
+                            sdk_util::ScopedRef<Mount>* out_mount) = 0;
 };
 
+}  // namespace nacl_io
+
 #endif  // LIBRARIES_NACL_IO_MOUNT_FACTORY_H_