set content length limit if half open range request fails

content/browser/download/download_file_impl.h

Index: content/browser/download/download_file_impl.h
diff --git a/content/browser/download/download_file_impl.h b/content/browser/download/download_file_impl.h
index e786c2b38b0fff0400e9f4d9bed85463b60b22b9..0a2cbd832993f36e25d42e619712bd0b48046a84 100644
--- a/content/browser/download/download_file_impl.h
+++ b/content/browser/download/download_file_impl.h
@@ -69,6 +69,7 @@ class CONTENT_EXPORT DownloadFileImpl : public DownloadFile {
                          const RenameCompletionCallback& callback) override;
   void Detach() override;
   void Cancel() override;
+  void SetPotentialFileLength(int64_t length) override;
   const base::FilePath& FullPath() const override;
   bool InProgress() const override;
   void WasPaused() override;
@@ -251,6 +252,10 @@ class CONTENT_EXPORT DownloadFileImpl : public DownloadFile {
   // Used to trigger progress updates.
   std::unique_ptr<base::RepeatingTimer> update_timer_;
 
+  // Potential file length. A range request with an offset larger than this
+  // value will fail. So the actual file length cannot be larger than this.
+  int64_t potential_file_length_;
+
   // Statistics
   size_t bytes_seen_;
   base::TimeDelta disk_writes_time_;