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

services/media/framework/allocator.cc

-// 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.
-
-#include <cstdlib>
-
-#include "base/logging.h"
-#include "services/media/framework/allocator.h"
-
-namespace mojo {
-namespace media {
-
-namespace {
-
-class DefaultAllocator : public Allocator {
- public:
-  constexpr DefaultAllocator() {}
-
-  // Allocator implementation.
-  void* AllocatePayloadBuffer(uint64_t size) override;
-
-  void ReleasePayloadBuffer(uint64_t size, void* buffer) override;
-};
-
-void* DefaultAllocator::AllocatePayloadBuffer(uint64_t size) {
-  DCHECK(size > 0);
-  return std::malloc(static_cast<size_t>(size));
-}
-
-void DefaultAllocator::ReleasePayloadBuffer(uint64_t size, void* buffer) {
-  DCHECK(size > 0);
-  DCHECK(buffer);
-  std::free(buffer);
-}
-
-static constexpr DefaultAllocator default_allocator;
-
-} // namespace
-
-// static
-Allocator* Allocator::GetDefault() {
-  return const_cast<DefaultAllocator*>(&default_allocator);
-}
-
-} // namespace media
-} // namespace mojo