Revert of Close the QUIC connection when non-crypto stream data is written at ENCRYPTION_NONE. Flag protected…

net/quic/quic_connection.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/quic/quic_connection.h"
 
 #include <string.h>
 #include <sys/types.h>
 
 #include <algorithm>
@@ skipping 1114 matching lines @@
     QuicStreamId id,
     const QuicIOVector& iov,
     QuicStreamOffset offset,
     bool fin,
     FecProtection fec_protection,
     QuicAckNotifier::DelegateInterface* delegate) {
   if (!fin && iov.total_length == 0) {
     LOG(DFATAL) << "Attempt to send empty stream frame";
     return QuicConsumedData(0, false);
   }
-  if (FLAGS_quic_never_write_unencrypted_data && id != kCryptoStreamId &&
-      encryption_level_ == ENCRYPTION_NONE) {
-    LOG(DFATAL) << "Cannot send stream data without encryption.";
-    CloseConnection(QUIC_UNENCRYPTED_STREAM_DATA, false);
-    return QuicConsumedData(0, false);
-  }
 
   // Opportunistically bundle an ack with every outgoing packet.
   // Particularly, we want to bundle with handshake packets since we don't know
   // which decrypter will be used on an ack packet following a handshake
   // packet (a handshake packet from client to server could result in a REJ or a
   // SHLO from the server, leading to two different decrypters at the server.)
   //
   // TODO(jri): Note that ConsumeData may cause a response packet to be sent.
   // We may end up sending stale ack information if there are undecryptable
   // packets hanging around and/or there are revivable packets which may get
@@ skipping 1169 matching lines @@
       packet_number_of_last_sent_packet_ + packets_between_mtu_probes_ + 1;
   ++mtu_probe_count_;
 
   DVLOG(2) << "Sending a path MTU discovery packet #" << mtu_probe_count_;
   SendMtuDiscoveryPacket(mtu_discovery_target_);
 
   DCHECK(!mtu_discovery_alarm_->IsSet());
 }
 
 }  // namespace net