When launching PNaCl helper nexes, explicitly disable IRT loading.

chrome/common/nacl_types.h

Index: chrome/common/nacl_types.h
diff --git a/chrome/common/nacl_types.h b/chrome/common/nacl_types.h
index 49ff63cfceb6668cce8d20f74800a9e92f17e669..ecb173858e0098050e285f492e7a3cfb4f11bfcd 100644
--- a/chrome/common/nacl_types.h
+++ b/chrome/common/nacl_types.h
@@ -57,6 +57,7 @@ struct NaClStartParams {
   bool enable_exception_handling;
   bool enable_debug_stub;
   bool enable_ipc_proxy;
+  bool uses_irt;
 };
 
 // Parameters sent to the browser process to have it launch a NaCl process.
@@ -65,13 +66,14 @@ struct NaClStartParams {
 // renderer_messages.h.
 struct NaClLaunchParams {
   NaClLaunchParams();
-  NaClLaunchParams(const std::string& u, int r, uint32 p);
+  NaClLaunchParams(const std::string& u, int r, uint32 p, bool uses_irt);
   NaClLaunchParams(const NaClLaunchParams& l);
   ~NaClLaunchParams();
 
   std::string manifest_url;
   int render_view_id;
   uint32 permission_bits;
+  bool uses_irt;
 };
 
 }  // namespace nacl