[SyncFS] Use variadic template in callback_helper.h

chrome/browser/sync_file_system/drive_backend/callback_helper.h

-// This file was GENERATED by command:
-//     pump.py callback_helper.h.pump
-// DO NOT EDIT BY HAND!!!
-
-
 // Copyright 2014 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 CHROME_BROWSER_SYNC_FILE_SYSTEM_DRIVE_BACKEND_CALLBACK_HELPER_H_
 #define CHROME_BROWSER_SYNC_FILE_SYSTEM_DRIVE_BACKEND_CALLBACK_HELPER_H_
 
 #include "base/bind.h"
 #include "base/location.h"
 #include "base/logging.h"
@@ skipping 49 matching lines @@
   scoped_refptr<base::SequencedTaskRunner> task_runner_;
   const tracked_objects::Location from_here_;
   scoped_ptr<base::Callback<T> > callback_;
 
   DISALLOW_COPY_AND_ASSIGN(CallbackHolder);
 };
 
 template <typename>
 struct RelayToTaskRunnerHelper;
 
-template <>
-struct RelayToTaskRunnerHelper<void()> {
-  static void Run(CallbackHolder<void()>* holder) {
+template <typename... Args>
+struct RelayToTaskRunnerHelper<void(Args...)> {
+  static void Run(CallbackHolder<void(Args...)>* holder, Args... args) {
     holder->task_runner()->PostTask(
-        holder->from_here(), base::Bind(holder->callback()));
+        holder->from_here(),
+        base::Bind(holder->callback(),
+                   RebindForward(args)...));
   }
 };
 
-template <typename A1>
-struct RelayToTaskRunnerHelper<void(A1)> {
-  static void Run(CallbackHolder<void(A1)>* holder, A1 a1) {
-    holder->task_runner()->PostTask(
-        holder->from_here(), base::Bind(holder->callback(), RebindForward(a1)));
-  }
-};
-
-template <typename A1, typename A2>
-struct RelayToTaskRunnerHelper<void(A1, A2)> {
-  static void Run(CallbackHolder<void(A1, A2)>* holder, A1 a1, A2 a2) {
-    holder->task_runner()->PostTask(
-        holder->from_here(), base::Bind(holder->callback(), RebindForward(a1),
-            RebindForward(a2)));
-  }
-};
-
-template <typename A1, typename A2, typename A3>
-struct RelayToTaskRunnerHelper<void(A1, A2, A3)> {
-  static void Run(CallbackHolder<void(A1, A2, A3)>* holder, A1 a1, A2 a2,
-      A3 a3) {
-    holder->task_runner()->PostTask(
-        holder->from_here(), base::Bind(holder->callback(), RebindForward(a1),
-            RebindForward(a2), RebindForward(a3)));
-  }
-};
-
-template <typename A1, typename A2, typename A3, typename A4>
-struct RelayToTaskRunnerHelper<void(A1, A2, A3, A4)> {
-  static void Run(CallbackHolder<void(A1, A2, A3, A4)>* holder, A1 a1, A2 a2,
-      A3 a3, A4 a4) {
-    holder->task_runner()->PostTask(
-        holder->from_here(), base::Bind(holder->callback(), RebindForward(a1),
-            RebindForward(a2), RebindForward(a3), RebindForward(a4)));
-  }
-};
-
-template <typename A1, typename A2, typename A3, typename A4, typename A5>
-struct RelayToTaskRunnerHelper<void(A1, A2, A3, A4, A5)> {
-  static void Run(CallbackHolder<void(A1, A2, A3, A4, A5)>* holder, A1 a1,
-      A2 a2, A3 a3, A4 a4, A5 a5) {
-    holder->task_runner()->PostTask(
-        holder->from_here(), base::Bind(holder->callback(), RebindForward(a1),
-            RebindForward(a2), RebindForward(a3), RebindForward(a4),
-            RebindForward(a5)));
-  }
-};
-
-template <typename A1, typename A2, typename A3, typename A4, typename A5,
-    typename A6>
-struct RelayToTaskRunnerHelper<void(A1, A2, A3, A4, A5, A6)> {
-  static void Run(CallbackHolder<void(A1, A2, A3, A4, A5, A6)>* holder, A1 a1,
-      A2 a2, A3 a3, A4 a4, A5 a5, A6 a6) {
-    holder->task_runner()->PostTask(
-        holder->from_here(), base::Bind(holder->callback(), RebindForward(a1),
-            RebindForward(a2), RebindForward(a3), RebindForward(a4),
-            RebindForward(a5), RebindForward(a6)));
-  }
-};
-
-template <typename A1, typename A2, typename A3, typename A4, typename A5,
-    typename A6, typename A7>
-struct RelayToTaskRunnerHelper<void(A1, A2, A3, A4, A5, A6, A7)> {
-  static void Run(CallbackHolder<void(A1, A2, A3, A4, A5, A6, A7)>* holder,
-      A1 a1, A2 a2, A3 a3, A4 a4, A5 a5, A6 a6, A7 a7) {
-    holder->task_runner()->PostTask(
-        holder->from_here(), base::Bind(holder->callback(), RebindForward(a1),
-            RebindForward(a2), RebindForward(a3), RebindForward(a4),
-            RebindForward(a5), RebindForward(a6), RebindForward(a7)));
-  }
-};
-
 }  // namespace internal
 
 template <typename T>
 base::Callback<T> RelayCallbackToTaskRunner(
     const scoped_refptr<base::SequencedTaskRunner>& task_runner,
     const tracked_objects::Location& from_here,
     const base::Callback<T>& callback) {
   DCHECK(task_runner->RunsTasksOnCurrentThread());
 
   if (callback.is_null())
@@ skipping 10 matching lines @@
     const base::Callback<T>& callback) {
   return RelayCallbackToTaskRunner(
       base::ThreadTaskRunnerHandle::Get(),
       from_here, callback);
 }
 
 }  // namespace drive_backend
 }  // namespace sync_file_system
 
 #endif  // CHROME_BROWSER_SYNC_FILE_SYSTEM_DRIVE_BACKEND_CALLBACK_HELPER_H_