Remove ack bundling mode.

gfe-relnote: Deprecate gfe2_reloadable_flag_quic_deprecate_ack_bundling_mode.
PiperOrigin-RevId: 253856112
Change-Id: Iaa62b97be5904743c56c5b48b230446a9c4bd870
diff --git a/quic/core/http/quic_spdy_client_stream.cc b/quic/core/http/quic_spdy_client_stream.cc
index 2903b30..5cbb79d 100644
--- a/quic/core/http/quic_spdy_client_stream.cc
+++ b/quic/core/http/quic_spdy_client_stream.cc
@@ -142,8 +142,7 @@
 size_t QuicSpdyClientStream::SendRequest(SpdyHeaderBlock headers,
                                          QuicStringPiece body,
                                          bool fin) {
-  QuicConnection::ScopedPacketFlusher flusher(
-      session_->connection(), QuicConnection::SEND_ACK_IF_QUEUED);
+  QuicConnection::ScopedPacketFlusher flusher(session_->connection());
   bool send_fin_with_headers = fin && body.empty();
   size_t bytes_sent = body.size();
   header_bytes_written_ =