Use Mojo pipes to signal sync IPC events

ppapi/nacl_irt/irt_ppapi.cc

Index: ppapi/nacl_irt/irt_ppapi.cc
diff --git a/ppapi/nacl_irt/irt_ppapi.cc b/ppapi/nacl_irt/irt_ppapi.cc
index 8d2f715b0cbea26bb7de5be3995707a8cf1a4a6f..7cf3b0dd6388dc17794464a7084f2ad7b50c5206 100644
--- a/ppapi/nacl_irt/irt_ppapi.cc
+++ b/ppapi/nacl_irt/irt_ppapi.cc
@@ -12,6 +12,7 @@
 
 #include "base/threading/thread.h"
 #include "ipc/ipc_logging.h"
+#include "mojo/edk/embedder/embedder.h"
 #include "ppapi/nacl_irt/irt_interfaces.h"
 #include "ppapi/nacl_irt/irt_ppapi.h"
 #include "ppapi/nacl_irt/plugin_startup.h"
@@ -32,6 +33,8 @@ void PpapiPluginRegisterThreadCreator(
 int irt_ppapi_start(const struct PP_StartFunctions* funcs) {
   g_pp_functions = *funcs;
 
+  mojo::edk::Init();

[Mark Seaborn, 2016/06/14 19:30:21]

It looks like you're doing this twice, once here and once in StartUpPlugin() in
ppapi/nacl_irt/plugin_startup.cc.  Only once should be necessary.

[Ken Rockot(use gerrit already), 2016/06/14 20:17:03]

Oops, removed from here

+
   base::MessageLoop loop;
   ppapi::proxy::PluginGlobals plugin_globals(
       scoped_refptr<base::TaskRunner>(ppapi::GetIOThread()->task_runner()));