workers: Remove dead code.

content/child/worker_thread_task_runner.cc

 // Copyright 2013 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.
 
 #include "content/child/worker_thread_task_runner.h"
 
 #include "base/logging.h"
 #include "content/child/worker_task_runner.h"
 
 namespace content {
 
 WorkerThreadTaskRunner::WorkerThreadTaskRunner(int worker_thread_id)
     : worker_thread_id_(worker_thread_id) {
 }
 
-scoped_refptr<WorkerThreadTaskRunner> WorkerThreadTaskRunner::current() {
-  int worker_thread_id = WorkerTaskRunner::Instance()->CurrentWorkerId();
-  if (!worker_thread_id)
-    return scoped_refptr<WorkerThreadTaskRunner>();
-  return make_scoped_refptr(new WorkerThreadTaskRunner(worker_thread_id));
-}
-
 bool WorkerThreadTaskRunner::PostDelayedTask(
     const tracked_objects::Location& /* from_here */,
     const base::Closure& task,
     base::TimeDelta delay) {
   // Currently non-zero delay is not supported.
   DCHECK(!delay.ToInternalValue());
   return WorkerTaskRunner::Instance()->PostTask(worker_thread_id_, task);
 }
 
 bool WorkerThreadTaskRunner::RunsTasksOnCurrentThread() const {
   return worker_thread_id_ == WorkerTaskRunner::Instance()->CurrentWorkerId();
 }
 
 WorkerThreadTaskRunner::~WorkerThreadTaskRunner() {}
 
 }  // namespace content