FBTF: Fix more ctor/dtors found by clang plugin.

media/base/filters.h

 // Copyright (c) 2010 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.
 
 // Filters are connected in a strongly typed manner, with downstream filters
 // always reading data from upstream filters.  Upstream filters have no clue
 // who is actually reading from them, and return the results via callbacks.
 //
 //                         DemuxerStream(Video) <- VideoDecoder <- VideoRenderer
 // DataSource <- Demuxer <
@@ skipping 252 matching lines @@
   // Indicate whether decoder provides its own output buffers
   virtual bool ProvidesBuffer() = 0;
 
  protected:
   // A video frame is ready to be consumed. This method invoke
   // |consume_video_frame_callback_| internally.
   void VideoFrameReady(scoped_refptr<VideoFrame> frame) {
     consume_video_frame_callback_->Run(frame);
   }
 
+  VideoDecoder();
+  virtual ~VideoDecoder();
+
  private:
   scoped_ptr<ConsumeVideoFrameCallback> consume_video_frame_callback_;
 };
 
 
 class AudioDecoder : public MediaFilter {
  public:
   static FilterType filter_type() {
     return FILTER_AUDIO_DECODER;
   }
@@ skipping 19 matching lines @@
   }
   ConsumeAudioSamplesCallback* consume_audio_samples_callback() {
      return consume_audio_samples_callback_.get();
    }
 
   // Renderer provides an output buffer for Decoder to write to. These buffers
   // will be recycled to renderer by fill_buffer_done_callback_;
   // We could also pass empty pointer here to let decoder provide buffers pool.
   virtual void ProduceAudioSamples(scoped_refptr<Buffer> buffer) = 0;
 
+ protected:
+  AudioDecoder();
+  ~AudioDecoder();
+
  private:
   scoped_ptr<ConsumeAudioSamplesCallback> consume_audio_samples_callback_;
 };
 
 
 class VideoRenderer : public MediaFilter {
  public:
   static FilterType filter_type() {
     return FILTER_VIDEO_RENDERER;
   }
@@ skipping 30 matching lines @@
   // buffer.
   virtual bool HasEnded() = 0;
 
   // Sets the output volume.
   virtual void SetVolume(float volume) = 0;
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_FILTERS_H_