Fix an issue that we didn't clean url request properly.

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 b3ce7d9259c8a57f2af114e9ef1ed22edc93719b..23533167701af1f1d30f9c3af3ad5003e5069278 100644
--- a/content/browser/download/download_file_impl.h
+++ b/content/browser/download/download_file_impl.h
@@ -13,6 +13,7 @@
 #include <memory>
 #include <string>
 #include <unordered_map>
+#include <unordered_set>
 #include <vector>
 
 #include "base/files/file.h"
@@ -249,6 +250,10 @@ class CONTENT_EXPORT DownloadFileImpl : public DownloadFile {
   // starting from offset.
   SourceStreams source_streams_;
 
+  // The offsets of the streams to be closed. Since ByteStreamReader can't close
+  // resource writing to the pipe, we need to close them on UI thread.
+  std::unordered_set<int64_t> streams_to_close_;
+
   // Used to trigger progress updates.
   std::unique_ptr<base::RepeatingTimer> update_timer_;