Split the PNaCl IRT shim into 3 pieces, and include one piece into IRT.

ppapi/proxy/irt_ppapi.c

Index: ppapi/proxy/irt_ppapi.c
diff --git a/ppapi/proxy/irt_ppapi.c b/ppapi/proxy/irt_ppapi.c
index 24dafdb077d605527c48074c5b599e273d27c30f..9a17a842e663fa024278dbbfc52bced9265fdd87 100644
--- a/ppapi/proxy/irt_ppapi.c
+++ b/ppapi/proxy/irt_ppapi.c
@@ -5,14 +5,16 @@
  */
 
 #include "native_client/src/public/irt_core.h"
+#include "native_client/src/trusted/service_runtime/include/sys/unistd.h"
 #include "native_client/src/untrusted/irt/irt.h"
 #include "native_client/src/untrusted/irt/irt_private.h"
 #include "ppapi/nacl_irt/irt_ppapi.h"
 #include "ppapi/proxy/plugin_main_irt.h"
+#include "ppapi/proxy/irt_shim_ppapi.h"
 
-struct PP_StartFunctions g_pp_functions;
+static struct PP_StartFunctions g_pp_functions;
 
-static int irt_ppapi_start(const struct PP_StartFunctions* funcs) {
+int irt_ppapi_start(const struct PP_StartFunctions* funcs) {
   /* Disable NaCl's open_resource() interface on this thread. */
   g_is_main_thread = 1;
 
@@ -38,9 +40,22 @@ static const struct nacl_irt_ppapihook nacl_irt_ppapihook = {
   PpapiPluginRegisterThreadCreator,
 };
 
+static int ppapihook_pnacl_private_filter(void) {
+  static int ppapihook_pnacl_private_enabled = -1;

[Mark Seaborn, 2014/02/26 22:11:03]

Since this will only be called once, you can leave out the complication of
trying to cache this (which is of slightly dubious thread safety).

[jvoung (off chromium), 2014/02/27 01:39:55]

True it'll only be called on startup -- done.

+  if (-1 == ppapihook_pnacl_private_enabled) {
+    ppapihook_pnacl_private_enabled = sysconf(NACL_ABI__SC_NACL_PNACL_MODE);
+    if (ppapihook_pnacl_private_enabled == -1)
+      ppapihook_pnacl_private_enabled = 0;
+  }
+  return ppapihook_pnacl_private_enabled;

[Mark Seaborn, 2014/02/26 22:11:03]

Since this isn't thread safe, this could end up returning -1 (for true) instead
of 0.

[jvoung (off chromium), 2014/02/27 01:39:55]

Changed to not use the static int.

+}
+
 static const struct nacl_irt_interface irt_interfaces[] = {
   { NACL_IRT_PPAPIHOOK_v0_1, &nacl_irt_ppapihook, sizeof(nacl_irt_ppapihook),
     NULL },
+  { NACL_IRT_PPAPIHOOK_PNACL_PRIVATE_v0_1,
+    &nacl_irt_ppapihook_pnacl_private, sizeof(nacl_irt_ppapihook_pnacl_private),
+    ppapihook_pnacl_private_filter },
 };
 
 static size_t chrome_irt_query(const char* interface_ident,