Remove media::FilterCollection::Clear() because no one calls it.

media/base/filter_collection.cc

 // 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.
 
 #include "media/base/filter_collection.h"
 
 #include "base/logging.h"
 #include "media/base/audio_renderer.h"
 #include "media/base/demuxer.h"
 #include "media/base/video_renderer.h"
@@ skipping 23 matching lines @@
 
 void FilterCollection::SetVideoRenderer(
     scoped_ptr<VideoRenderer> video_renderer) {
   video_renderer_ = video_renderer.Pass();
 }
 
 scoped_ptr<VideoRenderer> FilterCollection::GetVideoRenderer() {
   return video_renderer_.Pass();
 }
 
-void FilterCollection::Clear() {
-  audio_renderer_.reset();
-  video_renderer_.reset();
-}
-
 }  // namespace media