Add an IPC channel between the NaCl loader process and the renderer.

ppapi/c/private/ppb_nacl_private.h

Index: ppapi/c/private/ppb_nacl_private.h
===================================================================
--- ppapi/c/private/ppb_nacl_private.h	(revision 135227)
+++ ppapi/c/private/ppb_nacl_private.h	(working copy)
@@ -5,10 +5,11 @@
 #ifndef PPAPI_C_PRIVATE_PPB_NACL_UTIL_PRIVATE_H_
 #define PPAPI_C_PRIVATE_PPB_NACL_UTIL_PRIVATE_H_
 
+#include "ppapi/c/pp_instance.h"
 #include "ppapi/c/pp_resource.h"
 #include "ppapi/c/pp_stdint.h"
 
-#define PPB_NACL_PRIVATE_INTERFACE "PPB_NaCl(Private);0.4"
+#define PPB_NACL_PRIVATE_INTERFACE "PPB_NaCl(Private);0.5"
 
 struct PPB_NaCl_Private {
   // This function launches NaCl's sel_ldr process.  On success, the function
@@ -16,9 +17,15 @@
   // write |socket_count| nacl::Handles to imc_handles.  Unless
   // EnableBackgroundSelLdrLaunch is called, this method must be invoked from
   // the main thread.
-  bool (*LaunchSelLdr)(const char* alleged_url, int socket_count,
+  bool (*LaunchSelLdr)(PP_Instance instance,
+                       const char* alleged_url,
+                       int socket_count,
                        void* imc_handles);
 
+  // This function starts the PPAPI proxy so the nexe can communicate with the
+  // browser's renderer process.
+  bool (*StartPpapiProxy)(PP_Instance instance);
+
   // On POSIX systems, this function returns the file descriptor of
   // /dev/urandom.  On non-POSIX systems, this function returns 0.
   int (*UrandomFD)(void);