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

net/quic/core/crypto/local_strike_register_client_test.cc

Index: net/quic/core/crypto/local_strike_register_client_test.cc
diff --git a/net/quic/core/crypto/local_strike_register_client_test.cc b/net/quic/core/crypto/local_strike_register_client_test.cc
index e28e627ed44e904a3ba8645d8de57280c1025733..ee2ca16c9a1ffa5941e6171adca2c64ab202e5fe 100644
--- a/net/quic/core/crypto/local_strike_register_client_test.cc
+++ b/net/quic/core/crypto/local_strike_register_client_test.cc
@@ -81,7 +81,7 @@ TEST_F(LocalStrikeRegisterClientTest, CheckOrbit) {
 
 TEST_F(LocalStrikeRegisterClientTest, IncorrectNonceLength) {
   string valid_nonce;
-  uint32_t norder = htonl(kCurrentTimeExternalSecs);
+  uint32_t norder = base::HostToNet32(kCurrentTimeExternalSecs);
   valid_nonce.assign(reinterpret_cast<const char*>(&norder), sizeof(norder));
   valid_nonce.append(string(reinterpret_cast<const char*>(kOrbit), kOrbitSize));
   valid_nonce.append(string(20, '\x17'));  // 20 'random' bytes.