Support OnceCallback on base::ResetAndReturn

base/callback_helpers.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.
 
 // This defines helpful methods for dealing with Callbacks.  Because Callbacks
 // are implemented using templates, with a class per callback signature, adding
 // methods to Callback<> itself is unattractive (lots of extra code gets
 // generated).  Instead, consider adding methods here.
 //
 // ResetAndReturn(&cb) is like cb.Reset() but allows executing a callback (via a
 // copy) after the original callback is Reset().  This can be handy if Run()
 // reads/writes the variable holding the Callback.
 
 #ifndef BASE_CALLBACK_HELPERS_H_
 #define BASE_CALLBACK_HELPERS_H_
 
 #include "base/callback.h"
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 
 namespace base {
 
-template <typename Sig>
-base::Callback<Sig> ResetAndReturn(base::Callback<Sig>* cb) {
-  base::Callback<Sig> ret(*cb);
+template <typename Signature,
+          internal::CopyMode copy_mode,
+          internal::RepeatMode repeat_mode>
+base::Callback<Signature, copy_mode, repeat_mode> ResetAndReturn(
+    base::Callback<Signature, copy_mode, repeat_mode>* cb) {
+  base::Callback<Signature, copy_mode, repeat_mode> ret(*cb);
   cb->Reset();
   return ret;
 }
 
 // ScopedClosureRunner is akin to std::unique_ptr<> for Closures. It ensures
 // that the Closure is executed no matter how the current scope exits.
 class BASE_EXPORT ScopedClosureRunner {
  public:
   ScopedClosureRunner();
   explicit ScopedClosureRunner(const Closure& closure);
@@ skipping 16 matching lines @@
 
  private:
   Closure closure_;
 
   DISALLOW_COPY_AND_ASSIGN(ScopedClosureRunner);
 };
 
 }  // namespace base
 
 #endif  // BASE_CALLBACK_HELPERS_H_