Fix ReturnValue::Set.

include/v8.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 778 matching lines @@
 
  private:
   // TODO(dcarney): remove before cutover
   V8_INLINE(T* operator->() const) { return val_; }
  public:
 #endif
 
  private:
   template<class F> friend class Handle;
   template<class F> friend class Local;
+  template<class F> friend class ReturnValue;
   friend class ImplementationUtilities;
   friend class ObjectTemplate;
   friend class Context;
   friend class InternalHandleHelper;
   friend class LocalContext;
 
   V8_INLINE(static Persistent<T> New(Isolate* isolate, T* that));
 
 #ifndef V8_USE_UNSAFE_HANDLES
   T* val_;
@@ skipping 5492 matching lines @@
 
 
 }  // namespace v8
 
 
 #undef V8EXPORT
 #undef TYPE_CHECK
 
 
 #endif  // V8_H_