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

net/quic/core/quic_protocol.cc

Index: net/quic/core/quic_protocol.cc
diff --git a/net/quic/core/quic_protocol.cc b/net/quic/core/quic_protocol.cc
index 946ad05b69a3ed2fdd389a26770fc4c517c6a157..c6cf8620e05220392780661299740d38b4221fe1 100644
--- a/net/quic/core/quic_protocol.cc
+++ b/net/quic/core/quic_protocol.cc
@@ -146,16 +146,6 @@ QuicStreamFrame::QuicStreamFrame(QuicStreamId stream_id,
 
 QuicStreamFrame::~QuicStreamFrame() {}
 
-uint32_t MakeQuicTag(char a, char b, char c, char d) {
-  return static_cast<uint32_t>(a) | static_cast<uint32_t>(b) << 8 |
-         static_cast<uint32_t>(c) << 16 | static_cast<uint32_t>(d) << 24;
-}
-
-bool ContainsQuicTag(const QuicTagVector& tag_vector, QuicTag tag) {
-  return std::find(tag_vector.begin(), tag_vector.end(), tag) !=
-         tag_vector.end();
-}
-
 ostream& operator<<(ostream& os, const QuicPacketHeader& header) {
   os << "{ connection_id: " << header.public_header.connection_id
      << ", connection_id_length: " << header.public_header.connection_id_length