Partly change IRT load-skipping to be explicit.

src/trusted/service_runtime/sel_main_chrome.c

Index: src/trusted/service_runtime/sel_main_chrome.c
diff --git a/src/trusted/service_runtime/sel_main_chrome.c b/src/trusted/service_runtime/sel_main_chrome.c
index de792653e75d0dba4d22e5d9e71e20abe6affeea..173537d0b8a56527e430509a1fb8ed22b637db8f 100644
--- a/src/trusted/service_runtime/sel_main_chrome.c
+++ b/src/trusted/service_runtime/sel_main_chrome.c
@@ -308,17 +308,17 @@ void NaClChromeMainStart(struct NaClChromeMainArgs *args) {
    * Load the integrated runtime (IRT) library.
    * We check if there is a segment gap before trying to load the IRT.  This
    * is to support IRT-less / segment-gap-free PNaCl translator nexes.
-   * TODO(mseaborn): Plumb through a flag from Chrome in such cases,
-   * instead of looking for the absence of a segment gap, when the nexe does
-   * not follow NaCl's stable ABI.
+   * TODO(jvoung): Instead of looking for the absence of a segment gap,
+   * only allow irt_fd == -1, when the nexe does not follow NaCl's stable ABI.
    */
-  if (NULL != nap->text_shm) {
+  if (NULL != nap->text_shm && args->irt_fd != -1) {
     NaClLoadIrt(nap, args->irt_fd);
   } else {
     NaClLog(
-        LOG_WARNING,
-        "Main executable has no segment gap; skipping loading IRT library. "
-        "This is expected for PNaCl's translator nexes.\n");
+        1,
+        "Main executable has no segment gap or irt_fd == -1; "
+        "skipping loading IRT library. This is expected for PNaCl's "
+        "translator nexes.\n");
   }
 
   NACL_FI_FATAL("BeforeEnvCleanserCtor");