Add reverse dns lookup as a method on InternetAddress.

runtime/bin/socket_win.cc

Index: runtime/bin/socket_win.cc
diff --git a/runtime/bin/socket_win.cc b/runtime/bin/socket_win.cc
index bac17baff374821e53dc383847163cfc1e83400a..dbb06a02f51ca260ad56ac71186e7e37e22496ab 100644
--- a/runtime/bin/socket_win.cc
+++ b/runtime/bin/socket_win.cc
@@ -254,6 +254,27 @@ AddressList<SocketAddress>* Socket::LookupAddress(const char* host,
 }
 
 
+const char* Socket::ReverseLookup(RawAddr addr, OSError** os_error) {
+  char* host = new char[NI_MAXHOST];
+  int status = getnameinfo(&addr.addr,
+                           SocketAddress::GetAddrLength(&addr),
+                           host,
+                           NI_MAXHOST,
+                           NULL,
+                           0,
+                           NI_NAMEREQD);
+  if (status != 0) {
+    ASSERT(*os_error == NULL);
+    DWORD error_code = WSAGetLastError();
+    SetLastError(error_code);
+    *os_error = new OSError();
+    delete host;
+    return NULL;
+  }
+  return host;
+}
+
+
 AddressList<InterfaceSocketAddress>* Socket::ListInterfaces(
     int type,
     OSError** os_error) {