remoting: Cleanup class/struct fwd declarations

remoting/protocol/audio_writer.h

 // 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.
 
 #ifndef REMOTING_PROTOCOL_AUDIO_WRITER_H_
 #define REMOTING_PROTOCOL_AUDIO_WRITER_H_
 
 #include <memory>
 #include <string>
 
 #include "base/callback.h"
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "remoting/protocol/audio_stub.h"
 #include "remoting/protocol/channel_dispatcher_base.h"
 
-namespace net {
-class StreamSocket;
-}  // namespace net
-
 namespace remoting {
 namespace protocol {
 
-class Session;
 class SessionConfig;
 
 class AudioWriter : public ChannelDispatcherBase,
                     public AudioStub {
  public:
   // Once AudioWriter is created, the Init() method of ChannelDispatcherBase
   // should be used to initialize it for the session.
   static std::unique_ptr<AudioWriter> Create(const SessionConfig& config);
 
   ~AudioWriter() override;
 
   // AudioStub interface.
   void ProcessAudioPacket(std::unique_ptr<AudioPacket> packet,
                           const base::Closure& done) override;
 
  private:
   AudioWriter();
 
   void OnIncomingMessage(std::unique_ptr<CompoundBuffer> message) override;
 
   DISALLOW_COPY_AND_ASSIGN(AudioWriter);
 };
 
 }  // namespace protocol
 }  // namespace remoting
 
 #endif  // REMOTING_PROTOCOL_AUDIO_WRITER_H_