Reland: Remove reference counting from media::VideoDecoder and friends.

media/base/pipeline.cc

Index: media/base/pipeline.cc
diff --git a/media/base/pipeline.cc b/media/base/pipeline.cc
index 1b88deb10f5fc34eb810ba14899a7b033cadeb90..8d379c4b64c0c46b2c284d67d5f944e9365b1f7a 100644
--- a/media/base/pipeline.cc
+++ b/media/base/pipeline.cc
@@ -944,7 +944,6 @@ void Pipeline::InitializeVideoRenderer(const PipelineStatusCB& done_cb) {
   video_renderer_ = filter_collection_->GetVideoRenderer();
   video_renderer_->Initialize(
       stream,
-      *filter_collection_->GetVideoDecoders(),
       done_cb,
       base::Bind(&Pipeline::OnUpdateStatistics, this),
       base::Bind(&Pipeline::OnVideoTimeUpdate, this),
@@ -953,7 +952,6 @@ void Pipeline::InitializeVideoRenderer(const PipelineStatusCB& done_cb) {
       base::Bind(&Pipeline::SetError, this),
       base::Bind(&Pipeline::GetMediaTime, this),
       base::Bind(&Pipeline::GetMediaDuration, this));
-  filter_collection_->GetVideoDecoders()->clear();
 }
 
 void Pipeline::OnAudioUnderflow() {