Deprecate --gfe2_reloadable_flag_quic_add_packet_flusher_on_async_op_done.

PiperOrigin-RevId: 377968917

quic/core/quic_flags_list.h

diff --git a/quic/core/quic_flags_list.h b/quic/core/quic_flags_list.h
index 53dcdc4..c69f818 100644
--- a/quic/core/quic_flags_list.h
+++ b/quic/core/quic_flags_list.h
@@ -29,8 +29,6 @@
 QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_tls_retry_handshake_on_early_data, true)
 // If true, TlsServerHandshaker will allow proof_source_handle_ to be closed promptly.
 QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_tls_close_proof_source_handle_promptly, true)
-// If true, TlsServerHandshaker will install a packet flusher when async operation completes.
-QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_add_packet_flusher_on_async_op_done, true)
 // If true, TlsServerHandshaker will use handshake hints(if present) to speed up handshakes.
 QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_tls_server_use_handshake_hints, true)
 // If true, abort async QPACK header decompression in QuicSpdyStream::Reset() and in QuicSpdyStream::OnStreamReset().

quic/core/tls_handshaker.cc

diff --git a/quic/core/tls_handshaker.cc b/quic/core/tls_handshaker.cc
index 9ba5f3c..3e81210 100644
--- a/quic/core/tls_handshaker.cc
+++ b/quic/core/tls_handshaker.cc
@@ -96,12 +96,10 @@
     return;
   }
 
-  QUICHE_BUG_IF(quic_tls_server_async_done_no_flusher,
-                SSL_is_server(ssl()) && add_packet_flusher_on_async_op_done_ &&
-                    !handshaker_delegate_->PacketFlusherAttached())
-      << "is_server:" << SSL_is_server(ssl())
-      << ", add_packet_flusher_on_async_op_done_:"
-      << add_packet_flusher_on_async_op_done_;
+  QUICHE_BUG_IF(
+      quic_tls_server_async_done_no_flusher,
+      SSL_is_server(ssl()) && !handshaker_delegate_->PacketFlusherAttached())
+      << "is_server:" << SSL_is_server(ssl());
 
   QUIC_VLOG(1) << ENDPOINT << "Continuing handshake";
   int rv = SSL_do_handshake(ssl());

quic/core/tls_handshaker.h

diff --git a/quic/core/tls_handshaker.h b/quic/core/tls_handshaker.h
index 0b5ddc3..dba8ea5 100644
--- a/quic/core/tls_handshaker.h
+++ b/quic/core/tls_handshaker.h
@@ -168,9 +168,6 @@
   // error code corresponding to the TLS alert description |desc|.
   void SendAlert(EncryptionLevel level, uint8_t desc) override;
 
-  const bool add_packet_flusher_on_async_op_done_ =
-      GetQuicReloadableFlag(quic_add_packet_flusher_on_async_op_done);
-
   const bool retry_handshake_on_early_data_ =
       GetQuicReloadableFlag(quic_tls_retry_handshake_on_early_data);
 

quic/core/tls_server_handshaker.cc

diff --git a/quic/core/tls_server_handshaker.cc b/quic/core/tls_server_handshaker.cc
index 38a2499..d7a850e 100644
--- a/quic/core/tls_server_handshaker.cc
+++ b/quic/core/tls_server_handshaker.cc
@@ -351,18 +351,7 @@
 void TlsServerHandshaker::OverrideQuicConfigDefaults(QuicConfig* /*config*/) {}
 
 void TlsServerHandshaker::AdvanceHandshakeFromCallback() {
-  std::unique_ptr<QuicConnection::ScopedPacketFlusher> flusher;
-  if (add_packet_flusher_on_async_op_done_) {
-    if (session()->PacketFlusherAttached()) {
-      QUIC_RELOADABLE_FLAG_COUNT_N(quic_add_packet_flusher_on_async_op_done, 1,
-                                   2);
-    } else {
-      QUIC_RELOADABLE_FLAG_COUNT_N(quic_add_packet_flusher_on_async_op_done, 2,
-                                   2);
-    }
-    flusher = std::make_unique<QuicConnection::ScopedPacketFlusher>(
-        session()->connection());
-  }
+  QuicConnection::ScopedPacketFlusher flusher(session()->connection());
 
   AdvanceHandshake();
   if (!is_connection_closed()) {