net: Cleanup class/struct forward declarations

net/log/bounded_file_net_log_observer.h

 // Copyright 2016 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.
 
 #ifndef BOUNDED_FILE_NET_LOG_OBSERVER_H_
 #define BOUNDED_FILE_NET_LOG_OBSERVER_H_
 
 #include <queue>
 
 #include "base/files/file_path.h"
 #include "base/files/scoped_file.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
 #include "base/synchronization/lock.h"
 #include "base/threading/thread.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "net/base/net_export.h"
 #include "net/log/net_log.h"
 #include "net/log/net_log_capture_mode.h"
 
 namespace base {
-class DictionaryValue;
 class Value;
 }  // namespace base
 
 namespace net {
 
 class URLRequestContext;
 
 // BoundedFileNetLogObserver watches the NetLog event stream and sends all
 // entries to a group of files in the directory specified when observation
 // starts.
@@ skipping 93 matching lines @@
   // thread is safe because the FileWriter object will be alive until the
   // observer's destruction.
   FileWriter* file_writer_;
 
   DISALLOW_COPY_AND_ASSIGN(BoundedFileNetLogObserver);
 };
 
 }  // namespace net
 
 #endif  // BOUNDED_FILE_NET_LOG_OBSERVER_H_