Refactor BaseFile methods to return a DownloadInterruptReason instead of a net::Error.

content/browser/download/base_file_linux.cc

+// Copyright (c) 2012 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/download/base_file.h"
+
+#include "content/browser/download/file_metadata_linux.h"
+#include "content/public/browser/browser_thread.h"
+
+content::DownloadInterruptReason BaseFile::AnnotateWithSourceInformation() {
+  DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::FILE));
+  DCHECK(!detached_);
+
+  content::AddOriginMetadataToFile(full_path_, source_url_, referrer_url_);
+  return content::DOWNLOAD_INTERRUPT_REASON_NONE;
+}