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

net/quic/core/quic_versions.h

 // 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.
 
 #ifndef NET_QUIC_QUIC_VERSIONS_H_
 #define NET_QUIC_QUIC_VERSIONS_H_
 
 #include <string>
 #include <vector>
 
+#include "net/quic/core/quic_tag.h"
 #include "net/quic/core/quic_types.h"
 
 namespace net {
 
 // The available versions of QUIC. Guaranteed that the integer value of the enum
 // will match the version number.
 // When adding a new version to this enum you should add it to
 // kSupportedQuicVersions (if appropriate), and also add a new case to the
 // helper methods QuicVersionToQuicTag, QuicTagToQuicVersion, and
 // QuicVersionToString.
@@ skipping 54 matching lines @@
 NET_EXPORT_PRIVATE std::string QuicVersionToString(const QuicVersion version);
 
 // Returns comma separated list of string representations of QuicVersion enum
 // values in the supplied |versions| vector.
 NET_EXPORT_PRIVATE std::string QuicVersionVectorToString(
     const QuicVersionVector& versions);
 
 }  // namespace net
 
 #endif  // NET_QUIC_QUIC_VERSIONS_H_