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

services/media/framework/lpcm_util.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 SERVICES_MEDIA_FRAMEWORK_LPCM_UTIL_H_
 #define SERVICES_MEDIA_FRAMEWORK_LPCM_UTIL_H_
 
 #include <memory>
 
 #include "services/media/framework/stream_type.h"
 
 namespace mojo {
 namespace media {
 
 // Helper class that performs various LPCM processing functions.
 class LpcmUtil {
  public:
   static std::unique_ptr<LpcmUtil> Create(const LpcmStreamType& stream_type);
 
   virtual ~LpcmUtil() {}
 
   // Fills the buffer with silence.
-  virtual void Silence(void* buffer, uint64_t frame_count) const = 0;
+  virtual void Silence(void* buffer, size_t frame_count) const = 0;
 
   // Copies samples.
-  virtual void Copy(const void* in, void* out, uint64_t frame_count) const = 0;
+  virtual void Copy(const void* in, void* out, size_t frame_count) const = 0;
 
   // Mixes samples.
-  virtual void Mix(const void* in, void* out, uint64_t frame_count) const = 0;
+  virtual void Mix(const void* in, void* out, size_t frame_count) const = 0;
 
   // Interleaves non-interleaved samples. This assumes ffmpeg non-interleaved
   // ("planar") layout, in which the buffer (in) is divided evenly into a
   // channel buffer per channel. The samples for each channel are contiguous
   // in the respective channel buffer with possible empty space at the end
   // (hence the in_type_count and the frame_count).
   virtual void Interleave(
       const void* in,
-      uint64_t in_byte_count,
+      size_t in_byte_count,
       void* out,
-      uint64_t frame_count) const = 0;
+      size_t frame_count) const = 0;
 };
 
 }  // namespace media
 }  // namespace mojo
 
 #endif // SERVICES_MEDIA_FRAMEWORK_LPCM_UTIL_H_