When launching PNaCl helper nexes, explicitly disable IRT loading.

chrome/common/nacl_types.cc

Index: chrome/common/nacl_types.cc
diff --git a/chrome/common/nacl_types.cc b/chrome/common/nacl_types.cc
index 9b483572a033e61539c810760367402f1203d2f7..1dabb942f5db27e7d2b5a3eab6667f140173e1f3 100644
--- a/chrome/common/nacl_types.cc
+++ b/chrome/common/nacl_types.cc
@@ -8,7 +8,10 @@ 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() {
@@ -16,21 +19,25 @@ 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() {