content: Cleanup class/struct forward declarations

content/renderer/media/pepper_to_video_track_adapter.h

 // 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.
 
 #ifndef CONTENT_RENDERER_MEDIA_WEBRTC_VIDEO_DESTINATION_HANDLER_H_
 #define CONTENT_RENDERER_MEDIA_WEBRTC_VIDEO_DESTINATION_HANDLER_H_
 
 #include <stdint.h>
 
 #include <string>
 #include <vector>
 
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "content/common/content_export.h"
 
 namespace content {
 
-class PeerConnectionDependencyFactory;
 class MediaStreamRegistryInterface;
 class PPB_ImageData_Impl;
 
 // Interface used by a Pepper plugin to output frames to a video track.
 class CONTENT_EXPORT FrameWriterInterface {
  public:
   // The ownership of the |image_data| doesn't transfer. So the implementation
   // of this interface should make a copy of the |image_data| before return.
   virtual void PutFrame(PPB_ImageData_Impl* image_data,
                         int64_t time_stamp_ns) = 0;
@@ skipping 15 matching lines @@
                    const std::string& url,
                    FrameWriterInterface** frame_writer);
 
  private:
   DISALLOW_COPY_AND_ASSIGN(PepperToVideoTrackAdapter);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_MEDIA_WEBRTC_VIDEO_DESTINATION_HANDLER_H_