Disallow redundant Bind calls.

components/sync/base/bind_to_task_runner.h

 // Copyright 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 COMPONENTS_SYNC_BASE_BIND_TO_TASK_RUNNER_H_
 #define COMPONENTS_SYNC_BASE_BIND_TO_TASK_RUNNER_H_
 
 #include <memory>
 
 #include "base/bind.h"
@@ skipping 39 matching lines @@
 
 template <typename T>
 base::internal::PassedWrapper<ScopedVector<T>> TrampolineForward(
     ScopedVector<T>& p) {
   return base::Passed(&p);
 }
 
 template <typename Sig>
 struct BindToTaskRunnerTrampoline;
 
+template <>
+struct BindToTaskRunnerTrampoline<void()> {
+  static void Run(const scoped_refptr<base::TaskRunner>& task_runner,
+                  const base::Closure& cb) {
+    task_runner->PostTask(FROM_HERE, cb);
+  }
+};
+
 template <typename... Args>
 struct BindToTaskRunnerTrampoline<void(Args...)> {
   static void Run(const scoped_refptr<base::TaskRunner>& task_runner,
                   const base::Callback<void(Args...)>& cb,
                   Args... args) {
     task_runner->PostTask(FROM_HERE,
                           base::Bind(cb, TrampolineForward(args)...));
   }
 };
 
 }  // namespace bind_helpers
 
 template <typename T>
 base::Callback<T> BindToTaskRunner(
     const scoped_refptr<base::TaskRunner>& task_runner,
     const base::Callback<T>& cb) {
   return base::Bind(&bind_helpers::BindToTaskRunnerTrampoline<T>::Run,
                     task_runner, cb);
 }
 
 template <typename T>
 base::Callback<T> BindToCurrentThread(const base::Callback<T>& cb) {
   return BindToTaskRunner(base::ThreadTaskRunnerHandle::Get(), cb);
 }
 
 }  // namespace syncer
 
 #endif  // COMPONENTS_SYNC_BASE_BIND_TO_TASK_RUNNER_H_