Measure how often DNS hostnames aren't in preferred name form.

net/dns/dns_util_unittest.cc

Index: net/dns/dns_util_unittest.cc
diff --git a/net/dns/dns_util_unittest.cc b/net/dns/dns_util_unittest.cc
index 1d534716b6afead994e02d9789c3ef0f130371ed..c18c7427f9ce448e9263013955348df4e609559e 100644
--- a/net/dns/dns_util_unittest.cc
+++ b/net/dns/dns_util_unittest.cc
@@ -69,4 +69,26 @@ TEST_F(DNSUtilTest, DNSDomainToString) {
   EXPECT_EQ("", DNSDomainToString("\x06"));
 }
 
+TEST_F(DNSUtilTest, IsValidDNSDomain) {
+  const char* const bad_hostnames[] = {
+      "%20%20noodles.blorg", "noo dles.blorg ",    "noo dles.blorg. ",
+      "^noodles.blorg",      "noodles^.blorg",     "noo&dles.blorg",
+      "noodles.blorg`",      "www.-noodles.blorg",
+  };
+
+  for (size_t i = 0; i < arraysize(bad_hostnames); ++i) {
+    EXPECT_FALSE(IsValidDNSDomain(bad_hostnames[i]));
+  }
+
+  const char* const good_hostnames[] = {
+      "www.noodles.blorg",   "1www.noodles.blorg", "www.2noodles.blorg",
+      "www.n--oodles.blorg", "www.noodl_es.blorg", "www.no-_odles.blorg",
+      "www_.noodles.blorg",  "www.noodles.blorg.", "_privet._tcp.local",
+  };
+
+  for (size_t i = 0; i < arraysize(good_hostnames); ++i) {
+    EXPECT_TRUE(IsValidDNSDomain(good_hostnames[i]));
+  }
+}
+
 }  // namespace net