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

ppapi/native_client/src/trusted/plugin/module_ppapi.cc

Index: ppapi/native_client/src/trusted/plugin/module_ppapi.cc
===================================================================
--- ppapi/native_client/src/trusted/plugin/module_ppapi.cc	(revision 143037)
+++ ppapi/native_client/src/trusted/plugin/module_ppapi.cc	(working copy)
@@ -13,6 +13,8 @@
 #include "ppapi/c/private/ppb_nacl_private.h"
 #include "ppapi/cpp/module.h"
 
+StartPpapiProxyFunc start_ppapi_proxy;

[Mark Seaborn, 2012/06/20 19:24:40]

Does this have to be a global?  Can't plugin.cc call
GetBrowserInterface(PPB_NACL_PRIVATE_INTERFACE) itself?

[bbudge, 2012/06/21 00:00:46]

It could but I would have to duplicate the code here to get the interface, check
that it's non-NULL, print an error message if not. I'm just following the
pattern established by 'launch_nacl_process' here.

[Mark Seaborn, 2012/06/21 15:30:03]

Well, launch_nacl_process is a global for legacy reasons: it predates the
existence of the PPB_NaCl_Private interface.  Actually, it predates PPAPI too, I
think.  It's not a good pattern to copy. :-)

Extensive error checking for calling
GetBrowserInterface(PPB_NACL_PRIVATE_INTERFACE) isn't strictly necessary because
you will only get to this code after module_ppapi.cc has already checked this. 
So you could just do CHECK() instead of a non-NULL check + logging.  Given that
it's a Chromium-internal interface, a CHECK() is fine.

[bbudge, 2012/06/21 18:16:53]

Done.

+
 namespace plugin {
 
 class ModulePpapi : public pp::Module {
@@ -47,6 +49,9 @@
     launch_nacl_process = reinterpret_cast<LaunchNaClProcessFunc>(
         private_interface_->LaunchSelLdr);
 
+    start_ppapi_proxy = reinterpret_cast<StartPpapiProxyFunc>(
+        private_interface_->StartPpapiProxy);
+
 #if NACL_LINUX || NACL_OSX
     // Note that currently we do not need random numbers inside the
     // NaCl trusted plugin on Unix, but NaClSecureRngModuleInit() is