[net/dns] Serve requests from HOSTS file if possible.

net/dns/dns_test_util.h

Index: net/dns/dns_test_util.h
diff --git a/net/dns/dns_test_util.h b/net/dns/dns_test_util.h
index 8d8c0a6d4b4b2bd24e02139b2b35c8ad24aad331..e247be0c378e081d4ea589f7dfc35ce26d075dea 100644
--- a/net/dns/dns_test_util.h
+++ b/net/dns/dns_test_util.h
@@ -7,6 +7,8 @@
 #pragma once
 
 #include "base/basictypes.h"
+#include "base/memory/scoped_ptr.h"
+#include "net/dns/dns_config_service.h"
 #include "net/dns/dns_protocol.h"
 
 namespace net {
@@ -156,6 +158,25 @@ static const char* const kT3IpAddresses[] = {
 static const char kT3CanonName[] = "www.l.google.com";
 static const int kT3TTL = 0x00000015;
 
+class DnsClient;
+// Creates mock DnsClient for testing HostResolverImpl.
+scoped_ptr<DnsClient> CreateMockDnsClient(const DnsConfig& config);
+
+class MockDnsConfigService : public DnsConfigService {
+ public:
+  virtual ~MockDnsConfigService() {}
+
+  // Expose the protected methods for tests.
+  void ChangeConfig(const DnsConfig& config) {
+    DnsConfigService::OnConfigRead(config);
+  }
+
+  void ChangeHosts(const DnsHosts& hosts) {
+    DnsConfigService::OnHostsRead(hosts);
+  }
+};
+
+
 }  // namespace net
 
 #endif  // NET_DNS_DNS_TEST_UTIL_H_