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

chrome/nacl/nacl_listener.h

Index: chrome/nacl/nacl_listener.h
===================================================================
--- chrome/nacl/nacl_listener.h	(revision 137169)
+++ chrome/nacl/nacl_listener.h	(working copy)
@@ -19,6 +19,8 @@
 class SyncMessageFilter;
 }
 
+struct NaClDesc;
+
 // The NaClListener is an IPC channel listener that waits for a
 // request to start a NaCl module.
 class NaClListener : public IPC::Channel::Listener {
@@ -47,6 +49,8 @@
   // Used to identify what thread we're on.
   MessageLoop* main_loop_;
 
+  NaClDesc* nacl_ppapi_channel_;
+
   bool debug_enabled_;
 
   DISALLOW_COPY_AND_ASSIGN(NaClListener);