Don't try to change the alternate-protocol state of a server, if the

net/quic/quic_stream_factory.cc

Index: net/quic/quic_stream_factory.cc
diff --git a/net/quic/quic_stream_factory.cc b/net/quic/quic_stream_factory.cc
index a71787530d7460f974208b8441f45f6e98a2c740..9f103b7735a471c8a6515df1319ba9a6a894c3e6 100644
--- a/net/quic/quic_stream_factory.cc
+++ b/net/quic/quic_stream_factory.cc
@@ -837,13 +837,18 @@ void QuicStreamFactory::ProcessGoingAwaySession(
   if (!session_was_active)
     return;
 
+  const HostPortPair& server = server_id.host_port_pair();
+  // Don't try to change the alternate-protocol state, if the
+  // alternate-protocol state is unknown.
+  if (!http_server_properties_->HasAlternateProtocol(server))
+    return;
+
   // TODO(rch):  In the special case where the session has received no
   // packets from the peer, we should consider blacklisting this
   // differently so that we still race TCP but we don't consider the
   // session connected until the handshake has been confirmed.
   HistogramBrokenAlternateProtocolLocation(
       BROKEN_ALTERNATE_PROTOCOL_LOCATION_QUIC_STREAM_FACTORY);
-  const HostPortPair& server = server_id.host_port_pair();
   PortAlternateProtocolPair alternate =
       http_server_properties_->GetAlternateProtocol(server);
   DCHECK_EQ(QUIC, alternate.protocol);