Remove QuicUtils::ListTags and use ToDebugString() instead.

net/quic/core/quic_utils_test.cc

Index: net/quic/core/quic_utils_test.cc
diff --git a/net/quic/core/quic_utils_test.cc b/net/quic/core/quic_utils_test.cc
index 1830bc748c101d95f5e804694c76bf890ae38b32..57f57ffd1bceca45f7d64f3cd15dc592257a425e 100644
--- a/net/quic/core/quic_utils_test.cc
+++ b/net/quic/core/quic_utils_test.cc
@@ -35,13 +35,6 @@ TEST(QuicUtilsTest, TagToString) {
             QuicUtils::TagToString(MakeQuicTag('C', 'H', 'L', '\x1f')));
 }
 
-TEST(QuicUtilsTest, ListTags) {
-  QuicTagValueMap map;
-  map.insert(std::make_pair(kSCFG, "asd"));
-  map.insert(std::make_pair(kCHLO, "dsa"));
-  EXPECT_EQ("SCFG CHLO ", QuicUtils::ListTags(map));
-}
-
 TEST(QuicUtilsTest, ParseQuicConnectionOptions) {
   QuicTagVector empty_options = QuicUtils::ParseQuicConnectionOptions("");
   EXPECT_EQ(0ul, empty_options.size());