Motown: Remove LPCM optimizations, fix prepare, add flush, add ActiveMultistreamSink model/stage

services/media/framework/models/multistream_packet_source.h

-// Copyright 2016 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 MOJO_MEDIA_MODELS_MULTISTREAM_PACKET_SOURCE_H_
-#define MOJO_MEDIA_MODELS_MULTISTREAM_PACKET_SOURCE_H_
-
-#include <memory>
-
-#include "services/media/framework/packet.h"
-
-namespace mojo {
-namespace media {
-
-// Synchronous source of packets for multiple streams. This is currently used
-// by Demux, though it would be better if Demux were asynchronous.
-class MultiStreamPacketSource {
- public:
-  virtual ~MultiStreamPacketSource() {}
-
-  // Returns the number of streams the source produces.
-  virtual uint32_t stream_count() const = 0;
-
-  // Gets a packet for the stream indicated via stream_index_out. This call
-  // should always produce a packet until end-of-stream. The caller is
-  // responsible for releasing the packet.
-  virtual PacketPtr PullPacket(uint32_t *stream_index_out) = 0;
-};
-
-typedef std::shared_ptr<MultiStreamPacketSource> MultiStreamPacketSourcePtr;
-
-}  // namespace media
-}  // namespace mojo
-
-#endif // MOJO_MEDIA_MODELS_MULTISTREAM_PACKET_SOURCE_H_