arc: Reinstate lost error check

It was dropped in https://crrev.com/c/2464518 which may result in all
errors being reported as base::File::FILE_ERROR_NOT_FOUND.

Bug: 1049966
Change-Id: I78e1ac5bf664c49ecebf130d23737f8dad3721a9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2505341
Commit-Queue: Alexander Bolodurin <alexbn@google.com>
Reviewed-by: Ryo Hashimoto <hashimoto@chromium.org>
Cr-Commit-Position: refs/heads/master@{#825582}

chrome/browser/chromeos/arc/fileapi/arc_documents_provider_root.cc

@@ -293,10 +293,11 @@ void ArcDocumentsProviderRoot::GetFileInfoFromDocument(
     base::File::Error error,
     const mojom::DocumentPtr& document) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
-  if (document.is_null()) {
-    std::move(callback).Run(base::File::FILE_ERROR_NOT_FOUND, {});
+  if (error != base::File::FILE_OK) {
+    std::move(callback).Run(error, {});
     return;
   }
+  DCHECK(document);
 
   base::File::Info info;
   info.size = document->size;
@@ -712,10 +713,12 @@ void ArcDocumentsProviderRoot::GetExtraMetadataFromDocument(
     base::File::Error error,
     const mojom::DocumentPtr& document) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
-  if (document.is_null()) {
-    std::move(callback).Run(base::File::FILE_ERROR_NOT_FOUND, {});
+  if (error != base::File::FILE_OK) {
+    std::move(callback).Run(error, {});
     return;
   }
+  DCHECK(document);
+
   ExtraFileMetadata metadata;
   metadata.supports_delete = document->supports_delete;
   metadata.supports_rename = document->supports_rename;