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

net/quic/core/quic_utils.h

Index: net/quic/core/quic_utils.h
diff --git a/net/quic/core/quic_utils.h b/net/quic/core/quic_utils.h
index 203c7f831a5d9eb9a2ea2f18b1c4b7f836a2f153..ccab7a196a17bc6503d22496a1a7911b014f05f5 100644
--- a/net/quic/core/quic_utils.h
+++ b/net/quic/core/quic_utils.h
@@ -48,18 +48,6 @@ class NET_EXPORT_PRIVATE QuicUtils {
                                     const char* data2,
                                     int len2);
 
-  // FindMutualTag sets |out_result| to the first tag in the priority list that
-  // is also in the other list and returns true. If there is no intersection it
-  // returns false.
-  //
-  // If |out_index| is non-nullptr and a match is found then the index of that
-  // match in |their_tags| is written to |out_index|.
-  static bool FindMutualTag(const QuicTagVector& our_tags,
-                            const QuicTag* their_tags,
-                            size_t num_their_tags,
-                            QuicTag* out_result,
-                            size_t* out_index);
-
   // SerializeUint128 writes the first 96 bits of |v| in little-endian form
   // to |out|.
   static void SerializeUint128Short(uint128 v, uint8_t* out);
@@ -76,12 +64,6 @@ class NET_EXPORT_PRIVATE QuicUtils {
   // Returns TransmissionType as a char*
   static const char* TransmissionTypeToString(TransmissionType type);
 
-  // TagToString is a utility function for pretty-printing handshake messages
-  // that converts a tag to a string. It will try to maintain the human friendly
-  // name if possible (i.e. kABCD -> "ABCD"), or will just treat it as a number
-  // if not.
-  static std::string TagToString(QuicTag tag);
-
   // Returns the list of QUIC tags represented by the comma separated
   // string in |connection_options|.
   static QuicTagVector ParseQuicConnectionOptions(