PPAPI: Initialize CompletionCallbackWithOutput storage

ppapi/cpp/directory_entry.h

 // 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 PPAPI_CPP_DIRECTORY_ENTRY_H_
 #define PPAPI_CPP_DIRECTORY_ENTRY_H_
 
 #include <vector>
 
 #include "ppapi/c/pp_array_output.h"
@@ skipping 101 matching lines @@
   typedef DirectoryEntryArrayOutputAdapterWithStorage StorageType;
 
   static inline APIArgType StorageToAPIArg(StorageType& t) {
     return t.pp_array_output();
   }
 
   static inline std::vector<DirectoryEntry>& StorageToPluginArg(
       StorageType& t) {
     return t.output();
   }
+
+  static inline void Initialize(StorageType* /* t */) {}
 };
 
 }  // namespace internal
 }  // namespace pp
 
 #endif  // PPAPI_CPP_DIRECTORY_ENTRY_H_