Use FileNetLogObserver for implementing --log-net-log.

components/net_log/net_export_file_writer.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 "components/net_log/net_export_file_writer.h"
 
 #include <set>
 #include <utility>
 
 #include "base/bind.h"
@@ skipping 102 matching lines @@
     : state_(STATE_UNINITIALIZED),
       log_exists_(false),
       log_capture_mode_known_(false),
       log_capture_mode_(net::NetLogCaptureMode::Default()),
       chrome_net_log_(chrome_net_log),
       default_log_base_dir_getter_(base::Bind(&base::GetTempDir)),
       weak_ptr_factory_(this) {}
 
 NetExportFileWriter::~NetExportFileWriter() {
   if (file_net_log_observer_)
-    file_net_log_observer_->StopObserving(nullptr, base::Bind([] {}));
+    file_net_log_observer_->StopObserving(nullptr, base::Closure());
 }
 
 void NetExportFileWriter::AddObserver(StateObserver* observer) {
   DCHECK(thread_checker_.CalledOnValidThread());
   state_observer_list_.AddObserver(observer);
 }
 
 void NetExportFileWriter::RemoveObserver(StateObserver* observer) {
   DCHECK(thread_checker_.CalledOnValidThread());
   state_observer_list_.RemoveObserver(observer);
@@ skipping 234 matching lines @@
 
 void NetExportFileWriter::ResetObserverThenSetStateNotLogging() {
   DCHECK(thread_checker_.CalledOnValidThread());
   file_net_log_observer_.reset();
   state_ = STATE_NOT_LOGGING;
 
   NotifyStateObservers();
 }
 
 }  // namespace net_log