Fix some non-const ref function argument types.

net/quic/chromium/quic_stream_factory_test.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/chromium/quic_stream_factory.h"
 
 #include <memory>
 #include <ostream>
 #include <utility>
 
@@ skipping 384 matching lines @@
     return client_maker_.MakeInitialSettingsPacket(1, nullptr);
   }
 
   std::unique_ptr<QuicReceivedPacket> ConstructInitialSettingsPacket(
       QuicPacketNumber packet_number,
       QuicStreamOffset* offset) {
     return client_maker_.MakeInitialSettingsPacket(packet_number, offset);
   }
 
   // Helper method for server migration tests.
-  void VerifyServerMigration(QuicConfig& config, IPEndPoint expected_address) {
+  void VerifyServerMigration(const QuicConfig& config,
+                             IPEndPoint expected_address) {
     allow_server_migration_ = true;
     Initialize();
 
     ProofVerifyDetailsChromium verify_details = DefaultProofVerifyDetails();
     crypto_client_stream_factory_.AddProofVerifyDetails(&verify_details);
     crypto_client_stream_factory_.SetConfig(config);
 
     // Set up first socket data provider.
     MockQuicData socket_data1;
     socket_data1.AddRead(SYNCHRONOUS, ERR_IO_PENDING);
@@ skipping 4655 matching lines @@
   // Clear all cached states.
   factory_->ClearCachedStatesInCryptoConfig(
       base::Callback<bool(const GURL&)>());
   EXPECT_TRUE(test_cases[0].state->certs().empty());
   EXPECT_TRUE(test_cases[1].state->certs().empty());
   EXPECT_TRUE(test_cases[2].state->certs().empty());
 }
 
 }  // namespace test
 }  // namespace net