For Linux, create a ZygoteForkDelegate that uses the nacl_helper executable

chrome/nacl/nacl_main.cc

Index: chrome/nacl/nacl_main.cc
diff --git a/chrome/nacl/nacl_main.cc b/chrome/nacl/nacl_main.cc
index 64adb2ccb12a099351a4b2ca78fe7c0b40222fe9..e1564e22966b0cd935d17120b1693762dec21741 100644
--- a/chrome/nacl/nacl_main.cc
+++ b/chrome/nacl/nacl_main.cc
@@ -15,13 +15,15 @@
 #include "chrome/common/chrome_constants.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/logging_chrome.h"
-#include "chrome/nacl/nacl_launcher_thread.h"
+#include "chrome/nacl/nacl_listener.h"
 #include "chrome/nacl/nacl_main_platform_delegate.h"
 #include "content/common/child_process.h"
+#include "content/common/child_process_info.h"
 #include "content/common/hi_res_timer_manager.h"
 #include "content/common/main_function_params.h"
 #include "content/common/result_codes.h"
 #include "content/common/sandbox_policy.h"
+#include "ipc/ipc_switches.h"
 
 #if defined(OS_WIN)
 #include "chrome/nacl/broker_thread.h"
@@ -117,10 +119,8 @@ int NaClMain(const MainFunctionParams& parameters) {
   bool sandbox_test_result = platform.RunSandboxTests();
 
   if (sandbox_test_result) {
-    ChildProcess nacl_process;
-    bool debug = parsed_command_line.HasSwitch(switches::kEnableNaClDebug);
-    nacl_process.set_main_thread(new NaClLauncherThread(debug));
-    MessageLoop::current()->Run();
+    NaClListener listener;
+    listener.Listen();
   } else {
     // This indirectly prevents the test-harness-success-cookie from being set,
     // as a way of communicating test failure, because the nexe won't reply.