set content length limit if half open range request fails

content/browser/download/download_file.h

Index: content/browser/download/download_file.h
diff --git a/content/browser/download/download_file.h b/content/browser/download/download_file.h
index 33b444e68c27b9830a1b172d03550dafdda525fb..e579ed915fbbab74c084ae0ad979b8c7aad3f58c 100644
--- a/content/browser/download/download_file.h
+++ b/content/browser/download/download_file.h
@@ -75,6 +75,12 @@ class CONTENT_EXPORT DownloadFile {
   // Abort the download and automatically close the file.
   virtual void Cancel() = 0;
 
+  // Sets the potential file length. This can be called multiple times as

[David Trainor- moved to gerrit, 2017/04/03 17:47:31]

This comment seems really different from what the DCHECK says in the
implementation.

[qinmin, 2017/04/03 18:33:11]

Changed the comment for describing this call and half-open requests

+  // each parallel request is processing the stream independently. |length|
+  // may not be the actual file length, but it should not be smaller than
+  // it.
+  virtual void SetPotentialFileLength(int64_t length) = 0;
+
   virtual const base::FilePath& FullPath() const = 0;
   virtual bool InProgress() const = 0;
   virtual void WasPaused() = 0;