remoting: Cleanup class/struct fwd declarations

remoting/protocol/webrtc_audio_source_adapter.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 REMOTING_PROTOCOL_WEBRTC_AUDIO_SOURCE_ADAPTER_H_
 #define REMOTING_PROTOCOL_WEBRTC_AUDIO_SOURCE_ADAPTER_H_
 
 #include <memory>
 
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/observer_list.h"
 #include "base/single_thread_task_runner.h"
 #include "third_party/webrtc/api/mediastreaminterface.h"
 
 namespace webrtc {
 class AudioTrackSinkInterface;
 }  // namespace webrtc
 
 namespace remoting {
 
-class AudioPacket;
-
 namespace protocol {
 
 class AudioSource;
 
 class WebrtcAudioSourceAdapter : public webrtc::AudioSourceInterface {
  public:
   explicit WebrtcAudioSourceAdapter(
       scoped_refptr<base::SingleThreadTaskRunner> audio_task_runner);
   ~WebrtcAudioSourceAdapter() override;
 
@@ skipping 20 matching lines @@
   // Core running on |audio_task_runner_|.
   std::unique_ptr<Core> core_;
 
   DISALLOW_COPY_AND_ASSIGN(WebrtcAudioSourceAdapter);
 };
 
 }  // namespace protocol
 }  // namespace remoting
 
 #endif  // REMOTING_PROTOCOL_WEBRTC_AUDIO_SOURCE_ADAPTER_H_