Rename nacl::RefCounted to nacl::RefCountedThreadSafe

ppapi/native_client/src/shared/ppapi_proxy/plugin_ppb_buffer.h

-// Copyright 2011 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.
+// Copyright (c) 2011 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 NATIVE_CLIENT_SRC_SHARED_PPAPI_PROXY_PLUGIN_BUFFER_H_
 #define NATIVE_CLIENT_SRC_SHARED_PPAPI_PROXY_PLUGIN_BUFFER_H_
 
 #include "native_client/src/include/nacl_macros.h"
 #include "native_client/src/shared/ppapi_proxy/plugin_resource.h"
 #include "ppapi/c/dev/ppb_buffer_dev.h"
 
 namespace ppapi_proxy {
 
 // Implements the untrusted side of the PPB_Buffer interface.
 class PluginBuffer : public PluginResource {
  public:
   static const PPB_Buffer_Dev* GetInterface();
 
+ protected:
+  virtual ~PluginBuffer() {}
+
  private:
   IMPLEMENT_RESOURCE(PluginBuffer);
   NACL_DISALLOW_COPY_AND_ASSIGN(PluginBuffer);
 };
 
 }  // namespace ppapi_proxy
 
 #endif  // NATIVE_CLIENT_SRC_SHARED_PPAPI_PROXY_PLUGIN_BUFFER_H_