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_send_control_stream.cc b/quic/core/http/quic_send_control_stream.cc
index 7003b21..8002b0c 100644
--- a/quic/core/http/quic_send_control_stream.cc
+++ b/quic/core/http/quic_send_control_stream.cc
@@ -25,8 +25,7 @@
 void QuicSendControlStream::SendSettingsFrame(const SettingsFrame& settings) {
   DCHECK(!settings_sent_);
 
-  QuicConnection::ScopedPacketFlusher flusher(
-      session()->connection(), QuicConnection::SEND_ACK_IF_PENDING);
+  QuicConnection::ScopedPacketFlusher flusher(session()->connection());
   // Send the stream type on so the peer knows about this stream.
   char data[sizeof(kControlStream)];
   QuicDataWriter writer(QUIC_ARRAYSIZE(data), data);