Add GetBoundAddress to PPB_UDPSocket_Private

ppapi/c/private/ppb_udp_socket_private.h

Index: ppapi/c/private/ppb_udp_socket_private.h
diff --git a/ppapi/c/private/ppb_udp_socket_private.h b/ppapi/c/private/ppb_udp_socket_private.h
index 78722e0998b558cdad81901ebb9c4f7361594d9e..bbdbc1e6ba44f0036f877941dc8b8d184ec84e6a 100644
--- a/ppapi/c/private/ppb_udp_socket_private.h
+++ b/ppapi/c/private/ppb_udp_socket_private.h
@@ -38,7 +38,10 @@ struct PPB_UDPSocket_Private_0_2 {
    * Determines if a given resource is a UDP socket.
    */
   PP_Bool (*IsUDPSocket)(PP_Resource resource_id);
-  /* Creates a socket and binds to the address given by |addr|. */
+  /* Creates a socket and binds to the address given by |addr|.
+   * Returns the port number that the socket is bound to on
+   * success, 0 on failure
+   */
   int32_t (*Bind)(PP_Resource udp_socket,
                   const struct PP_NetAddress_Private* addr,
                   struct PP_CompletionCallback callback);