Close the QUIC connection when non-crypto stream data is written at ENCRYPTION_NONE.

net/quic/quic_connection.cc

Index: net/quic/quic_connection.cc
diff --git a/net/quic/quic_connection.cc b/net/quic/quic_connection.cc
index d981506eeef112f0acd49db3ad0e993314c5f524..2bb8d0e829e149360d4e2d2aae5337548d8180f0 100644
--- a/net/quic/quic_connection.cc
+++ b/net/quic/quic_connection.cc
@@ -1112,6 +1112,12 @@ QuicConsumedData QuicConnection::SendStreamData(
     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