Glue parallel download job and download file together.

content/browser/download/download_create_info.h

Index: content/browser/download/download_create_info.h
diff --git a/content/browser/download/download_create_info.h b/content/browser/download/download_create_info.h
index 174fded169ade9ae4f99c689987daa6c18aba238..a69f4bace435560758b777dc07e361a02156aee1 100644
--- a/content/browser/download/download_create_info.h
+++ b/content/browser/download/download_create_info.h
@@ -59,9 +59,16 @@ struct CONTENT_EXPORT DownloadCreateInfo {
   // The time when the download started.
   base::Time start_time;
 
-  // The total download size.
+  // The size of the response body. If content-length response header is not
+  // presented or can't be parse, set to 0.
   int64_t total_bytes;
 
+  // The starting position of the request to save to the target file.
+  // This value matches the offset in DownloadSaveInfo.
+  // TODO(xingliu): Remove this after we refactor DownloadJob to own
+  // DownloadFile.
+  int64_t offset;
+
   // True if the download was initiated by user action.
   bool has_user_gesture;