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

services/media/framework/models/active_multistream_sink.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_ACTIVE_MULTISTREAM_SINK_H_
+#define MOJO_MEDIA_MODELS_ACTIVE_MULTISTREAM_SINK_H_
+
+#include "services/media/framework/models/demand.h"
+#include "services/media/framework/models/part.h"
+#include "services/media/framework/packet.h"
+
+namespace mojo {
+namespace media {
+
+// Host for ActiveMultistreamSink.
+class ActiveMultistreamSinkHost {
+ public:
+  virtual ~ActiveMultistreamSinkHost() {}
+
+  // TODO(dalesat): Revisit allocation semantics.
+
+  // Allocates an input and returns its index.
+  virtual size_t AllocateInput() = 0;
+
+  // Releases a previously-allocated input and returns the container size
+  // required to hold the remaining inputs (i.e. max input index + 1). The
+  // return value can be used to resize the caller's input container.
+  virtual size_t ReleaseInput(size_t index) = 0;
+
+  // Updates demand for the specified input.
+  virtual void UpdateDemand(size_t input_index, Demand demand) = 0;
+};
+
+// Synchronous sink of packets for multiple streams.
+class ActiveMultistreamSink : public Part {
+ public:
+  ~ActiveMultistreamSink() override {}
+
+  // Sets the host callback interface.
+  virtual void SetHost(ActiveMultistreamSinkHost* host) = 0;
+
+  // Initiates demand.
+  virtual void Prime() = 0;
+
+  // Supplies a packet to the sink, returning the new demand for the input.
+  virtual Demand SupplyPacket(size_t input_index, PacketPtr packet) = 0;
+};
+
+}  // namespace media
+}  // namespace mojo
+
+#endif // MOJO_MEDIA_MODELS_ACTIVE_MULTISTREAM_SINK_H_