Update from https://crrev.com/316786

net/disk_cache/blockfile/backend_impl_v3.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 "net/disk_cache/blockfile/backend_impl_v3.h"
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
 #include "base/hash.h"
 #include "base/message_loop/message_loop.h"
 #include "base/metrics/field_trial.h"
 #include "base/metrics/histogram.h"
-#include "base/metrics/stats_counters.h"
 #include "base/rand_util.h"
 #include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
 #include "base/sys_info.h"
 #include "base/threading/thread_restrictions.h"
 #include "base/time/time.h"
 #include "base/timer/timer.h"
 #include "net/base/net_errors.h"
 #include "net/disk_cache/blockfile/disk_format_v3.h"
 #include "net/disk_cache/blockfile/entry_impl_v3.h"
@@ skipping 1501 matching lines @@
 }
 
 void BackendImplV3::OnExternalCacheHit(const std::string& key) {
   NOTIMPLEMENTED();
 }
 
 void BackendImplV3::CleanupCache() {
 }
 
 }  // namespace disk_cache