Remove QuicheStreamBufferAllocator platform API

The only file that used is no longer inside QUICHE proper.

PiperOrigin-RevId: 476061692
diff --git a/build/source_list.bzl b/build/source_list.bzl
index 4269322..266e20f 100644
--- a/build/source_list.bzl
+++ b/build/source_list.bzl
@@ -943,7 +943,6 @@
 ]
 epoll_tool_support_hdrs = [
     "common/platform/api/quiche_event_loop.h",
-    "common/platform/api/quiche_stream_buffer_allocator.h",
     "common/platform/api/quiche_udp_socket_platform_api.h",
     "quic/core/batch_writer/quic_batch_writer_base.h",
     "quic/core/batch_writer/quic_batch_writer_buffer.h",
diff --git a/build/source_list.gni b/build/source_list.gni
index 57eab18..7b04267 100644
--- a/build/source_list.gni
+++ b/build/source_list.gni
@@ -943,7 +943,6 @@
 ]
 epoll_tool_support_hdrs = [
     "src/quiche/common/platform/api/quiche_event_loop.h",
-    "src/quiche/common/platform/api/quiche_stream_buffer_allocator.h",
     "src/quiche/common/platform/api/quiche_udp_socket_platform_api.h",
     "src/quiche/quic/core/batch_writer/quic_batch_writer_base.h",
     "src/quiche/quic/core/batch_writer/quic_batch_writer_buffer.h",
diff --git a/build/source_list.json b/build/source_list.json
index 1c6503f..19cac11 100644
--- a/build/source_list.json
+++ b/build/source_list.json
@@ -942,7 +942,6 @@
   ],
   "epoll_tool_support_hdrs": [
     "quiche/common/platform/api/quiche_event_loop.h",
-    "quiche/common/platform/api/quiche_stream_buffer_allocator.h",
     "quiche/common/platform/api/quiche_udp_socket_platform_api.h",
     "quiche/quic/core/batch_writer/quic_batch_writer_base.h",
     "quiche/quic/core/batch_writer/quic_batch_writer_buffer.h",
diff --git a/quiche/common/platform/api/quiche_stream_buffer_allocator.h b/quiche/common/platform/api/quiche_stream_buffer_allocator.h
deleted file mode 100644
index 16e5e7c..0000000
--- a/quiche/common/platform/api/quiche_stream_buffer_allocator.h
+++ /dev/null
@@ -1,16 +0,0 @@
-// Copyright (c) 2019 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 QUICHE_COMMON_PLATFORM_API_QUICHE_STREAM_BUFFER_ALLOCATOR_H_
-#define QUICHE_COMMON_PLATFORM_API_QUICHE_STREAM_BUFFER_ALLOCATOR_H_
-
-#include "quiche_platform_impl/quiche_stream_buffer_allocator_impl.h"
-
-namespace quiche {
-
-using QuicheStreamBufferAllocator = QuicheStreamBufferAllocatorImpl;
-
-}
-
-#endif  // QUICHE_COMMON_PLATFORM_API_QUICHE_STREAM_BUFFER_ALLOCATOR_H_