Use a QuicSession member to latch
gfe2_reloadable_flag_quic_eliminate_static_stream_map_2.

This prevents unexpected behavior from runtime flag flipping.

gfe-relnote: gfe2_reloadable_flag_quic_eliminate_static_stream_map_2 replaces
gfe2_reloadable_flag_quic_eliminate_static_stream_map for rollout purposes.
PiperOrigin-RevId: 246926123
Change-Id: I11103af393e7fa93ea5b2d3cd90f9fe423fbed96
diff --git a/quic/core/quic_session.h b/quic/core/quic_session.h
index b24e5b6..172c52c 100644
--- a/quic/core/quic_session.h
+++ b/quic/core/quic_session.h
@@ -575,6 +575,10 @@
 
   StreamHandler GetOrCreateStreamImpl(QuicStreamId stream_id, bool may_buffer);
 
+  const bool eliminate_static_stream_map() const {
+    return eliminate_static_stream_map_;
+  }
+
  private:
   friend class test::QuicSessionPeer;
 
@@ -717,6 +721,9 @@
   // Supported version list used by the crypto handshake only. Please note, this
   // list may be a superset of the connection framer's supported versions.
   ParsedQuicVersionVector supported_versions_;
+
+  //  Latched value of quic_eliminate_static_stream_map.
+  const bool eliminate_static_stream_map_;
 };
 
 }  // namespace quic