Add Reset to ScopedClosureRunner.

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/basictypes.h"
 #include "base/callback.h"
+#include "base/compiler_specific.h"
 
 namespace base {
 
 template <typename Sig>
 base::Callback<Sig> ResetAndReturn(base::Callback<Sig>* cb) {
   base::Callback<Sig> ret(*cb);
   cb->Reset();
   return ret;
 }
 
+// ScopedClosureRunner is akin to scoped_ptr for Closures. It ensures that the
+// Closure is executed and deleted no matter how the current scope exits.
+class BASE_EXPORT ScopedClosureRunner {
+ public:
+  ScopedClosureRunner();
+  explicit ScopedClosureRunner(const Closure& closure);
+  ~ScopedClosureRunner();
+
+  void Reset();
+  void Reset(const Closure& closure);
+  Closure Release() WARN_UNUSED_RESULT;
+
+ private:
+  Closure closure_;
+
+  DISALLOW_COPY_AND_ASSIGN(ScopedClosureRunner);
+};
+
 }  // namespace base
 
 #endif  // BASE_CALLBACK_HELPERS_H_