[iOS/OS X] Allow base::scoped_nsobject<> to be used when ARC is enabled.

base/mac/bind_objc_block.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 BASE_MAC_BIND_OBJC_BLOCK_H_
 #define BASE_MAC_BIND_OBJC_BLOCK_H_
 
 #include <Block.h>
 
 #include "base/bind.h"
@@ skipping 28 matching lines @@
   return extracted_block(args...);
 }
 
 }  // namespace internal
 
 // Construct a callback from an objective-C block with up to six arguments (see
 // note above).
 template<typename R, typename... Args>
 base::Callback<R(Args...)> BindBlock(R(^block)(Args...)) {
   return base::Bind(&base::internal::RunBlock<R, Args...>,
-                    base::mac::ScopedBlock<R(^)(Args...)>(Block_copy(block)));
+                    base::mac::ScopedBlock<R (^)(Args...)>(
+                        base::mac::internal::ScopedBlockTraitsRetain(block)));
 }
 
 }  // namespace base
 
 #endif  // BASE_MAC_BIND_OBJC_BLOCK_H_