[NaCl SDK] Add nacl_io and sdk_util namespaces.

native_client_sdk/src/libraries/nacl_io/mount_dev.h

 /* Copyright (c) 2012 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_DEV_H_
 #define LIBRARIES_NACL_IO_MOUNT_DEV_H_
 
 #include "nacl_io/mount.h"
 #include "nacl_io/typed_mount_factory.h"
 
+namespace nacl_io {
+
 class MountNode;
 
 class MountDev : public Mount {
  public:
   virtual Error Access(const Path& path, int a_mode);
   virtual Error Open(const Path& path, int mode, ScopedMountNode* out_node);
   virtual Error Unlink(const Path& path);
   virtual Error Mkdir(const Path& path, int permissions);
   virtual Error Rmdir(const Path& path);
   virtual Error Remove(const Path& path);
 
  protected:
   MountDev();
 
   virtual Error Init(int dev, StringMap_t& args, PepperInterface* ppapi);
 
  private:
   ScopedMountNode root_;
 
   friend class TypedMountFactory<MountDev>;
   DISALLOW_COPY_AND_ASSIGN(MountDev);
 };
 
+}  // namespace nacl_io
+
 #endif  // LIBRARIES_NACL_IO_MOUNT_DEV_H_