Fix and refactor downloaded file handling in the loading stack

content/browser/loader/downloaded_temp_file_impl.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 "content/browser/loader/downloaded_temp_file_impl.h"
+
+#include "content/browser/loader/resource_dispatcher_host_impl.h"
+#include "mojo/public/cpp/bindings/strong_binding.h"
+
+namespace content {
+
+// static
+mojo::InterfacePtr<mojom::DownloadedTempFile> DownloadedTempFileImpl::Create(
+    int child_id,
+    int request_id) {
+  mojo::InterfacePtr<mojom::DownloadedTempFile> ptr;
+  auto binding = mojo::MakeStrongBinding(
+      base::MakeUnique<DownloadedTempFileImpl>(child_id, request_id),
+      mojo::GetProxy(&ptr));
+  return ptr;
+}
+
+DownloadedTempFileImpl::~DownloadedTempFileImpl() {
+  ResourceDispatcherHostImpl::Get()->UnregisterDownloadedTempFile(child_id_,
+                                                                  request_id_);
+}
+DownloadedTempFileImpl::DownloadedTempFileImpl(int child_id, int request_id)
+    : child_id_(child_id), request_id_(request_id) {}
+
+}  // namespace content