[net/dns] Isolate DnsConfigWatcher from DnsConfigService.

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 0cbdf948ca9e3d69e43d4bc423272be28653fbd0..051f595e5a87df15c5b3806970690b9f06f03bdf 100644
--- a/net/dns/dns_test_util.cc
+++ b/net/dns/dns_test_util.cc
@@ -163,8 +163,18 @@ scoped_ptr<DnsClient> CreateMockDnsClient(const DnsConfig& config) {
   return scoped_ptr<DnsClient>(new MockDnsClient(config));
 }
 
-void MockDnsConfigService::Watch(const CallbackType& callback) {
-  set_callback(callback);
+MockDnsConfigService::~MockDnsConfigService() {
+}
+
+void MockDnsConfigService::OnDNSChanged(unsigned detail) {
+}
+
+void MockDnsConfigService::ChangeConfig(const DnsConfig& config) {
+  DnsConfigService::OnConfigRead(config);
+}
+
+void MockDnsConfigService::ChangeHosts(const DnsHosts& hosts) {
+  DnsConfigService::OnHostsRead(hosts);
 }
 
 }  // namespace net