Range request support for parallel download in DownloadRequestCore.

content/public/browser/download_url_parameters.h

Index: content/public/browser/download_url_parameters.h
diff --git a/content/public/browser/download_url_parameters.h b/content/public/browser/download_url_parameters.h
index 41b0ed637bdbb3dca8662e6c0309594f734e94f7..88121d8c0363f231e8f7b67d2d4726e02076d965 100644
--- a/content/public/browser/download_url_parameters.h
+++ b/content/public/browser/download_url_parameters.h
@@ -168,9 +168,16 @@ class CONTENT_EXPORT DownloadUrlParameters {
   }
 
   // If |offset| is non-zero, then a byte range request will be issued to fetch
-  // the range of bytes starting at |offset| through to the end of thedownload.
+  // the range of bytes starting at |offset|.
+  // Use |set_length| to specify the last byte position, or the range
+  // request will be "Range:bytes={offset}-" to retrieve the rest of the file.
   void set_offset(int64_t offset) { save_info_.offset = offset; }
 
+  // When |length| > 0, the range of bytes will be from
+  // |save_info_.offset| to |save_info_.offset| + |length| - 1.
+  // See |DownloadSaveInfo.length|.
+  void set_length(int64_t length) { save_info_.length = length; }
+
   // If |offset| is non-zero, then |hash_of_partial_file| contains the raw
   // SHA-256 hash of the first |offset| bytes of the target file. Only
   // meaningful if a partial file exists and is identified by either the
@@ -239,6 +246,7 @@ class CONTENT_EXPORT DownloadUrlParameters {
     return save_info_.suggested_name;
   }
   int64_t offset() const { return save_info_.offset; }
+  int64_t length() const { return save_info_.length; }
   const std::string& hash_of_partial_file() const {
     return save_info_.hash_of_partial_file;
   }