Prototype: Use Chromium IPC for plugin LOAD_MODULE.

ppapi/native_client/src/trusted/plugin/service_runtime.h

Index: ppapi/native_client/src/trusted/plugin/service_runtime.h
diff --git a/ppapi/native_client/src/trusted/plugin/service_runtime.h b/ppapi/native_client/src/trusted/plugin/service_runtime.h
index 30200b85d5a9ba31f13638738a110abbabc1e768..6fbc9235b653ef37a7f45de1a506211290dd2688 100644
--- a/ppapi/native_client/src/trusted/plugin/service_runtime.h
+++ b/ppapi/native_client/src/trusted/plugin/service_runtime.h
@@ -232,7 +232,8 @@ class ServiceRuntime {
   // Spawn the sel_ldr instance. On success, returns true.
   // On failure, returns false and |error_string| is set to something
   // describing the error.
-  bool StartSelLdr(const SelLdrStartParams& params);
+  void StartSelLdr(const SelLdrStartParams& params,
+                   PP_CompletionCallback callback);
 
   // If starting sel_ldr from a background thread, wait for sel_ldr to
   // actually start.
@@ -292,6 +293,8 @@ class ServiceRuntime {
   NaClCondVar cond_;
   int exit_status_;
   bool start_sel_ldr_done_;
+
+  PP_Var start_sel_ldr_error_message_;
 };
 
 }  // namespace plugin