Moves QuicTag typedefs, and QuicTag utility methods to quic_tag.{h,cc}. No behavior change.

net/tools/quic/end_to_end_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 <stddef.h>
 #include <sys/epoll.h>
 
 #include <cstdint>
 #include <list>
 #include <memory>
@@ skipping 91 matching lines @@
     os << "{ server_supported_versions: "
        << QuicVersionVectorToString(p.server_supported_versions);
     os << " client_supported_versions: "
        << QuicVersionVectorToString(p.client_supported_versions);
     os << " negotiated_version: " << QuicVersionToString(p.negotiated_version);
     os << " client_supports_stateless_rejects: "
        << p.client_supports_stateless_rejects;
     os << " server_uses_stateless_rejects_if_peer_supported: "
        << p.server_uses_stateless_rejects_if_peer_supported;
     os << " congestion_control_tag: "
-       << QuicUtils::TagToString(p.congestion_control_tag);
+       << QuicTagToString(p.congestion_control_tag);
     os << " disable_hpack_dynamic_table: " << p.disable_hpack_dynamic_table;
     os << " force_hol_blocking: " << p.force_hol_blocking;
     os << " use_cheap_stateless_reject: " << p.use_cheap_stateless_reject
        << " }";
     return os;
   }
 
   QuicVersionVector client_supported_versions;
   QuicVersionVector server_supported_versions;
   QuicVersion negotiated_version;
@@ skipping 2836 matching lines @@
   client_->WaitForResponse();
   EXPECT_EQ(kBarResponseBody, client_->response_body());
   QuicConnectionStats client_stats =
       client_->client()->session()->connection()->GetStats();
   EXPECT_EQ(0u, client_stats.packets_lost);
   EXPECT_EQ(1, client_->client()->GetNumSentClientHellos());
 }
 }  // namespace
 }  // namespace test
 }  // namespace net