Fix and refactor downloaded file handling in the loading stack

content/browser/loader/resource_dispatcher_host_impl.cc

Index: content/browser/loader/resource_dispatcher_host_impl.cc
diff --git a/content/browser/loader/resource_dispatcher_host_impl.cc b/content/browser/loader/resource_dispatcher_host_impl.cc
index 3709943c1e1ffdd47c11040dd10576328fbd223c..213fe28203ea8f7cc0a47a4f90a8fc7e8f2fc931 100644
--- a/content/browser/loader/resource_dispatcher_host_impl.cc
+++ b/content/browser/loader/resource_dispatcher_host_impl.cc
@@ -45,6 +45,7 @@
 #include "content/browser/loader/async_resource_handler.h"
 #include "content/browser/loader/async_revalidation_manager.h"
 #include "content/browser/loader/detachable_resource_handler.h"
+#include "content/browser/loader/downloaded_temp_file_impl.h"
 #include "content/browser/loader/intercepting_resource_handler.h"
 #include "content/browser/loader/loader_delegate.h"
 #include "content/browser/loader/mime_sniffing_resource_handler.h"
@@ -1766,12 +1767,13 @@ void ResourceDispatcherHostImpl::OnDidChangePriority(
 }
 
 void ResourceDispatcherHostImpl::RegisterDownloadedTempFile(
-    int child_id, int request_id, const base::FilePath& file_path) {
-  scoped_refptr<ShareableFileReference> reference =
-      ShareableFileReference::Get(file_path);
-  DCHECK(reference.get());
+    std::unique_ptr<DownloadedTempFileImpl> downloaded_file) {
+  int child_id = downloaded_file->child_id();
+  int request_id = downloaded_file->request_id();
+  scoped_refptr<storage::ShareableFileReference> reference =
+      downloaded_file->reference();
 
-  registered_temp_files_[child_id][request_id] = reference;
+  registered_temp_files_[child_id][request_id] = std::move(downloaded_file);
   ChildProcessSecurityPolicyImpl::GetInstance()->GrantReadFile(
       child_id, reference->path());