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..ab724b9b90d50c3528a23b8146742686446eb91b 100644
--- a/content/browser/download/download_create_info.h
+++ b/content/browser/download/download_create_info.h
@@ -62,6 +62,9 @@ struct CONTENT_EXPORT DownloadCreateInfo {
   // The total download size.
   int64_t total_bytes;
 
+  // The starting position of the request to save to the target file.
+  int64_t offset;
+
   // True if the download was initiated by user action.
   bool has_user_gesture;