When launching PNaCl helper nexes, explicitly disable IRT loading.

chrome/common/nacl_types.cc

 // Copyright (c) 2012 The Chromium 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 "chrome/common/nacl_types.h"
 
 namespace nacl {
 
 NaClStartParams::NaClStartParams()
     : validation_cache_enabled(false),
-      enable_exception_handling(false) {
+      enable_exception_handling(false),
+      enable_debug_stub(false),
+      enable_ipc_proxy(false),
+      uses_irt(false) {
 }
 
 NaClStartParams::~NaClStartParams() {
 }
 
 NaClLaunchParams::NaClLaunchParams()
     : render_view_id(0),
-      permission_bits(0) {
+      permission_bits(0),
+      uses_irt(false) {
 }
 
 NaClLaunchParams::NaClLaunchParams(const std::string& manifest_url_,
                                    int render_view_id_,
-                                   uint32 permission_bits_)
+                                   uint32 permission_bits_,
+                                   bool uses_irt_)
     : manifest_url(manifest_url_),
       render_view_id(render_view_id_),
-      permission_bits(permission_bits_) {
+      permission_bits(permission_bits_),
+      uses_irt(uses_irt_) {
 }
 
 NaClLaunchParams::NaClLaunchParams(const NaClLaunchParams& l) {
   manifest_url = l.manifest_url;
   render_view_id = l.render_view_id;
   permission_bits = l.permission_bits;
+  uses_irt = l.uses_irt;
 }
 
 NaClLaunchParams::~NaClLaunchParams() {
 }
 
 }  // namespace nacl