Make ERR_ICANN_NAME_COLLISION work for async DNS resolver.

net/dns/dns_test_util.cc

Index: net/dns/dns_test_util.cc
diff --git a/net/dns/dns_test_util.cc b/net/dns/dns_test_util.cc
index 24ce6fbb3755a40468374b355b623a3abe398249..2de2c69bdd4c81f9484114cd75e4fa628f8b3aba 100644
--- a/net/dns/dns_test_util.cc
+++ b/net/dns/dns_test_util.cc
@@ -57,6 +57,13 @@ class MockTransaction : public DnsTransaction,
           (hostname.compare(0, prefix.size(), prefix) == 0)) {
         result_ = rules[i].result;
         delayed_ = rules[i].delay;
+
+        // Fill in an IP address for the result if one was not specified.
+        if (result_.ip.empty() && result_.type == MockDnsClientRule::OK) {
+          result_.ip = qtype_ == dns_protocol::kTypeA
+                           ? IPAddress::IPv4Localhost()
+                           : IPAddress::IPv6Localhost();
+        }
         break;
       }
     }
@@ -86,7 +93,7 @@ class MockTransaction : public DnsTransaction,
 
  private:
   void Finish() {
-    switch (result_) {
+    switch (result_.type) {
       case MockDnsClientRule::EMPTY:
       case MockDnsClientRule::OK: {
         std::string qname;
@@ -101,22 +108,21 @@ class MockTransaction : public DnsTransaction,
             reinterpret_cast<dns_protocol::Header*>(buffer);
         header->flags |= dns_protocol::kFlagResponse;
 
-        if (MockDnsClientRule::OK == result_) {
+        if (MockDnsClientRule::OK == result_.type) {
           const uint16_t kPointerToQueryName =
               static_cast<uint16_t>(0xc000 | sizeof(*header));
 
           const uint32_t kTTL = 86400;  // One day.
 
           // Size of RDATA which is a IPv4 or IPv6 address.
-          size_t rdata_size = qtype_ == dns_protocol::kTypeA
-                                  ? IPAddress::kIPv4AddressSize
-                                  : IPAddress::kIPv6AddressSize;
+          EXPECT_TRUE(result_.ip.IsValid());
+          size_t rdata_size = result_.ip.size();
 
           // 12 is the sum of sizes of the compressed name reference, TYPE,
           // CLASS, TTL and RDLENGTH.
           size_t answer_size = 12 + rdata_size;
 
-          // Write answer with loopback IP address.
+          // Write the answer using the expected IP address.
           header->ancount = base::HostToNet16(1);
           base::BigEndianWriter writer(buffer + nbytes, answer_size);
           writer.WriteU16(kPointerToQueryName);
@@ -124,14 +130,7 @@ class MockTransaction : public DnsTransaction,
           writer.WriteU16(dns_protocol::kClassIN);
           writer.WriteU32(kTTL);
           writer.WriteU16(static_cast<uint16_t>(rdata_size));
-          if (qtype_ == dns_protocol::kTypeA) {
-            char kIPv4Loopback[] = { 0x7f, 0, 0, 1 };
-            writer.WriteBytes(kIPv4Loopback, sizeof(kIPv4Loopback));
-          } else {
-            char kIPv6Loopback[] = { 0, 0, 0, 0, 0, 0, 0, 0,
-                                     0, 0, 0, 0, 0, 0, 0, 1 };
-            writer.WriteBytes(kIPv6Loopback, sizeof(kIPv6Loopback));
-          }
+          writer.WriteBytes(result_.ip.bytes().data(), rdata_size);
           nbytes += answer_size;
         }
         EXPECT_TRUE(response.InitParse(nbytes, query));