When launching PNaCl helper nexes, explicitly disable IRT loading.

ppapi/c/private/ppb_nacl_private.h

Index: ppapi/c/private/ppb_nacl_private.h
diff --git a/ppapi/c/private/ppb_nacl_private.h b/ppapi/c/private/ppb_nacl_private.h
index 42a6a712a350ff93f82e3fba4e6312dd80d3e02b..0b315cb04e9003ec03a05cd38044e48dfd11666f 100644
--- a/ppapi/c/private/ppb_nacl_private.h
+++ b/ppapi/c/private/ppb_nacl_private.h
@@ -3,7 +3,7 @@
  * found in the LICENSE file.
  */
 
-/* From private/ppb_nacl_private.idl modified Thu Dec 13 13:40:29 2012. */
+/* From private/ppb_nacl_private.idl modified Thu Jan  3 12:40:35 2013. */
 
 #ifndef PPAPI_C_PRIVATE_PPB_NACL_PRIVATE_H_
 #define PPAPI_C_PRIVATE_PPB_NACL_PRIVATE_H_
@@ -69,12 +69,15 @@ struct PPB_NaCl_Private_1_0 {
    * indicates that the nexe run by sel_ldr will use the PPAPI APIs.
    * This implies that LaunchSelLdr is run from the main thread.  If a nexe
    * does not need PPAPI, then it can run off the main thread.
+   * The |uses_irt| flag indicates if a nexe depends on the IRT or not.
+   * This is true for ABI stable nexes.
    */
   PP_NaClResult (*LaunchSelLdr)(PP_Instance instance,
                                 const char* alleged_url,
                                 PP_Bool uses_ppapi,
                                 PP_Bool enable_ppapi_dev,
                                 int32_t socket_count,
+                                PP_Bool uses_irt,
                                 void* imc_handles);
   /* This function starts the IPC proxy so the nexe can communicate with the
    * browser. Returns PP_NACL_OK on success, otherwise a result code indicating