Removed QuicStreamIdManager::set_largest_peer_created_stream_id().

This change also includes a minor refactor in quic_stream_id_manager.cc with no behavior change.

gfe-relnote: unused code. not protected.
PiperOrigin-RevId: 301465430
Change-Id: I8c8013e4b4b211a45912216f3038a0ff60efdfce
diff --git a/quic/core/quic_session.cc b/quic/core/quic_session.cc
index 83792db..2e12f5b 100644
--- a/quic/core/quic_session.cc
+++ b/quic/core/quic_session.cc
@@ -1628,11 +1628,7 @@
 
 void QuicSession::set_largest_peer_created_stream_id(
     QuicStreamId largest_peer_created_stream_id) {
-  if (VersionHasIetfQuicFrames(transport_version())) {
-    v99_streamid_manager_.SetLargestPeerCreatedStreamId(
-        largest_peer_created_stream_id);
-    return;
-  }
+  DCHECK(!VersionHasIetfQuicFrames(transport_version()));
   stream_id_manager_.set_largest_peer_created_stream_id(
       largest_peer_created_stream_id);
 }