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

services/media/framework/models/lpcm_transform.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_LPCM_TRANSFORM_H_
-#define MOJO_MEDIA_MODELS_LPCM_TRANSFORM_H_
-
-#include <memory>
-
-#include "services/media/framework/models/lpcm_frame_buffer.h"
-#include "services/media/framework/stream_type.h"
-
-namespace mojo {
-namespace media {
-
-// Synchronous lpcm transform.
-class LpcmTransform {
- public:
-  virtual ~LpcmTransform() {}
-
-  // Gets the input stream type.
-  virtual const LpcmStreamType& input_stream_type() const = 0;
-
-  // Gets the output stream type.
-  virtual const LpcmStreamType& output_stream_type() const = 0;
-
-  // Processes frames.
-  virtual void TransformFrames(
-      LpcmFrameBuffer* source,
-      LpcmFrameBuffer* dest,
-      bool mix) = 0;
-};
-
-typedef std::shared_ptr<LpcmTransform> LpcmTransformPtr;
-
-}  // namespace media
-}  // namespace mojo
-
-#endif // MOJO_MEDIA_MODELS_LPCM_TRANSFORM_H_