Disallow redundant Bind calls.

media/base/bind_to_current_loop.h

 // Copyright (c) 2015 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 MEDIA_BASE_BIND_TO_CURRENT_LOOP_H_
 #define MEDIA_BASE_BIND_TO_CURRENT_LOOP_H_
 
 #include <memory>
 
 #include "base/bind.h"
@@ skipping 31 matching lines @@
 
 template <typename T>
 base::internal::PassedWrapper<ScopedVector<T> > TrampolineForward(
     ScopedVector<T>& p) { return base::Passed(&p); }
 
 // First, tell the compiler TrampolineHelper is a struct template with one
 // type parameter.  Then define specializations where the type is a function
 // returning void and taking zero or more arguments.
 template <typename Sig> struct TrampolineHelper;
 
+template <>
+struct TrampolineHelper<void()> {
+  static void Run(
+      const scoped_refptr<base::SingleThreadTaskRunner>& task_runner,
+      const base::Closure& cb) {
+    task_runner->PostTask(FROM_HERE, cb);
+  }
+};
+
 template <typename... Args>
 struct TrampolineHelper<void(Args...)> {
   static void Run(
       const scoped_refptr<base::SingleThreadTaskRunner>& task_runner,
       const base::Callback<void(Args...)>& cb,
       Args... args) {
     task_runner->PostTask(FROM_HERE,
                           base::Bind(cb, TrampolineForward(args)...));
   }
 };
 
 }  // namespace internal
 
 template<typename T>
 static base::Callback<T> BindToCurrentLoop(
     const base::Callback<T>& cb) {
   return base::Bind(&internal::TrampolineHelper<T>::Run,
                     base::ThreadTaskRunnerHandle::Get(), cb);
 }
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_BIND_TO_CURRENT_LOOP_H_