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

media/base/filters.cc

 // 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.
 
 #include "media/base/filters.h"
 
 #include "base/logging.h"
 #include "base/message_loop.h"
 
 namespace media {
@@ skipping 61 matching lines @@
   }
 }
 
 void MediaFilter::OnAudioRendererDisabled() {
 }
 
 MediaFilter::~MediaFilter() {}
 
 DemuxerStream::~DemuxerStream() {}
 
+VideoDecoder::VideoDecoder() {}
+
+VideoDecoder::~VideoDecoder() {}
+
+AudioDecoder::AudioDecoder() {}
+
+AudioDecoder::~AudioDecoder() {}
+
 }  // namespace media