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

src/trusted/service_runtime/sel_ldr.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 <string.h>
 
 /*
  * NaCl Simple/secure ELF loader (NaCl SEL).
@@ skipping 246 matching lines @@
 
   nap->running = 0;
   nap->exit_status = -1;
 
 #if NACL_ARCH(NACL_BUILD_ARCH) == NACL_x86 && NACL_BUILD_SUBARCH == 32
   nap->code_seg_sel = 0;
   nap->data_seg_sel = 0;
 #endif
 
   nap->debug_stub_callbacks = NULL;
+  nap->debug_stub_port = 0;
   nap->main_nexe_desc = NULL;
   nap->irt_nexe_desc = NULL;
 
   nap->exception_handler = 0;
   if (!NaClMutexCtor(&nap->exception_mu)) {
     goto cleanup_desc_mu;
   }
   nap->enable_exception_handling = 0;
 #if NACL_WINDOWS
   nap->debug_exception_handler_state = NACL_DEBUG_EXCEPTION_HANDLER_NOT_STARTED;
@@ skipping 1054 matching lines @@
   nacl_global_xlate_base = mem_start;
 
   NaClSandboxMemoryStartForValgrind(mem_start);
 
   _ovly_debug_event();
 }
 
 void NaClGdbHook(struct NaClApp const *nap) {
   StopForDebuggerInit(nap->mem_start);
 }