Provide chrome the option of learning the debug stub port chosen by nacl.

src/trusted/service_runtime/sel_main_chrome.c

 /*
  * Copyright (c) 2012 The Native Client Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "native_client/src/public/chrome_main.h"
 
 #include "native_client/src/include/portability.h"
 #include "native_client/src/include/portability_io.h"
@@ skipping 58 matching lines @@
   args->imc_bootstrap_handle = NACL_INVALID_HANDLE;
   args->irt_fd = -1;
   args->enable_exception_handling = 0;
   args->enable_debug_stub = 0;
   args->enable_dyncode_syscalls = 1;
   args->pnacl_mode = 0;
   args->initial_nexe_max_code_bytes = 0;  /* No limit */
 #if NACL_LINUX || NACL_OSX
   args->debug_stub_server_bound_socket_fd = NACL_INVALID_SOCKET;
 #endif
+  args->debug_stub_server_port_selected_handler_func = NULL;
   args->create_memory_object_func = NULL;
   args->validation_cache = NULL;
 #if NACL_WINDOWS
   args->broker_duplicate_handle_func = NULL;
   args->attach_debug_exception_handler_func = NULL;
 #endif
 #if NACL_LINUX || NACL_OSX
   args->number_of_cores = -1;  /* unknown */
 #endif
 #if NACL_LINUX
@@ skipping 216 matching lines @@
 
   if (args->enable_debug_stub) {
 #if NACL_LINUX || NACL_OSX
     if (args->debug_stub_server_bound_socket_fd != NACL_INVALID_SOCKET) {
       NaClDebugSetBoundSocket(args->debug_stub_server_bound_socket_fd);
     }
 #endif
     if (!NaClDebugInit(nap)) {
       goto done;
     }
+    if (NULL != args->debug_stub_server_port_selected_handler_func) {
+      args->debug_stub_server_port_selected_handler_func(nap->debug_stub_port);
+    }
   }
 
   free(args);
   return LOAD_OK;
 
 done:
   fflush(stdout);
 
   /*
    * If there is a secure command channel, we sent an RPC reply with
@@ skipping 74 matching lines @@
    */
   NaClExit(ret_code);
 }
 
 void NaClChromeMainStartApp(struct NaClApp *nap,
                             struct NaClChromeMainArgs *args) {
   if (NaClChromeMainLoad(nap, args) != 0)
     NaClExit(1);
   NaClChromeMainStart(nap);
 }