[NaCl SDK] Add nacl_io and sdk_util namespaces.

native_client_sdk/src/libraries/sdk_util/ref_object.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_SDK_UTIL_REF_OBJECT
 #define LIBRARIES_SDK_UTIL_REF_OBJECT
 
 #include <stdlib.h>
 #include "pthread.h"
 
 #include "sdk_util/atomicops.h"
 
+namespace sdk_util {
+
 class ScopedRefBase;
 
 /*
  * RefObject
  *
  * A reference counted object. RefObjects should only be handled by ScopedRef
  * objects.
  *
  * When the object is first created, it has a reference count of zero.  It's
  * first incremented when it gets assigned to a ScopedRef.  When the last
@@ skipping 36 matching lines @@
     }
     return true;
   }
 
  private:
   Atomic32 ref_count_;
 
   friend class ScopedRefBase;
 };
 
+}  // namespace sdk_util
+
 #endif  // LIBRARIES_SDK_UTIL_REF_OBJECT