Remove task.h and finish base::Bind() migration.

base/threading/worker_pool_win.cc

 // 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.
 
 #include "base/threading/worker_pool.h"
 
 #include "base/bind.h"
+#include "base/callback.h"
 #include "base/debug/trace_event.h"
 #include "base/logging.h"
 #include "base/pending_task.h"
-#include "base/task.h"
 #include "base/tracked_objects.h"
 
 namespace base {
 
 namespace {
 
 DWORD CALLBACK WorkItemCallback(void* param) {
   PendingTask* pending_task = static_cast<PendingTask*>(param);
   UNSHIPPED_TRACE_EVENT2("task", "WorkItemCallback::Run",
                          "src_file", pending_task->posted_from.file_name(),
@@ skipping 30 matching lines @@
 
 }  // namespace
 
 bool WorkerPool::PostTask(const tracked_objects::Location& from_here,
                           const base::Closure& task, bool task_is_slow) {
   PendingTask* pending_task = new PendingTask(from_here, task);
   return PostTaskInternal(pending_task, task_is_slow);
 }
 
 }  // namespace base