Remove unused base/threading/worker_pool.h includes.

net/disk_cache/simple/simple_index.cc

 // Copyright (c) 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 "net/disk_cache/simple/simple_index.h"
 
 #include <algorithm>
 #include <limits>
 #include <string>
 #include <utility>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/files/file_enumerator.h"
 #include "base/files/file_util.h"
 #include "base/logging.h"
 #include "base/message_loop/message_loop.h"
 #include "base/metrics/field_trial.h"
 #include "base/numerics/safe_conversions.h"
 #include "base/pickle.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_tokenizer.h"
 #include "base/task_runner.h"
-#include "base/threading/worker_pool.h"
 #include "base/time/time.h"
 #include "base/trace_event/memory_usage_estimator.h"
 #include "net/base/net_errors.h"
 #include "net/disk_cache/simple/simple_entry_format.h"
 #include "net/disk_cache/simple/simple_histogram_macros.h"
 #include "net/disk_cache/simple/simple_index_delegate.h"
 #include "net/disk_cache/simple/simple_index_file.h"
 #include "net/disk_cache/simple/simple_synchronous_entry.h"
 #include "net/disk_cache/simple/simple_util.h"
 
@@ skipping 478 matching lines @@
                        start - last_write_to_disk_);
     }
   }
   last_write_to_disk_ = start;
 
   index_file_->WriteToDisk(reason, entries_set_, cache_size_, start,
                            app_on_background_, base::Closure());
 }
 
 }  // namespace disk_cache