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

base/mac/bind_objc_block.h

Index: base/mac/bind_objc_block.h
diff --git a/base/mac/bind_objc_block.h b/base/mac/bind_objc_block.h
index c31f26e5a31f6347fc2459848f0d261a8e4c4bf4..2434d444f5c4b6c275fad2161c75c9de63f93b85 100644
--- a/base/mac/bind_objc_block.h
+++ b/base/mac/bind_objc_block.h
@@ -45,8 +45,11 @@ R RunBlock(base::mac::ScopedBlock<R(^)(Args...)> block, Args... args) {
 // 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)));
+  return base::Bind(
+      &base::internal::RunBlock<R, Args...>,
+      base::mac::ScopedBlock<R (^)(Args...)>(
+          base::mac::internal::ScopedBlockTraits<R (^)(Args...)>::Retain(
+              block)));
 }
 
 }  // namespace base