Remove unnecessary code in QuicSpdySession.

gfe-relnote: no behavior change. Not protected.
PiperOrigin-RevId: 279846831
Change-Id: Ifdb1c868b5e633a6c9a70de51e4fe3098b7fc7e2

quic/core/http/quic_spdy_stream.h

diff --git a/quic/core/http/quic_spdy_stream.h b/quic/core/http/quic_spdy_stream.h
index ea413cf..317bfc5 100644
--- a/quic/core/http/quic_spdy_stream.h
+++ b/quic/core/http/quic_spdy_stream.h
@@ -211,8 +211,6 @@
   // will be available.
   bool IsClosed() { return sequencer()->IsClosed(); }
 
-  using QuicStream::CloseWriteSide;
-
   // QpackDecodedHeadersAccumulator::Visitor implementation.
   void OnHeadersDecoded(QuicHeaderList headers) override;
   void OnHeaderDecodingError() override;