Add limitation that LoadNexeAndStart must be called on the main thread.

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

 // -*- c++ -*-
 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // The portable representation of an instance and root scriptable object.
 // The PPAPI version of the plugin instantiates a subclass of this class.
 
 #ifndef NATIVE_CLIENT_SRC_TRUSTED_PLUGIN_PLUGIN_H_
 #define NATIVE_CLIENT_SRC_TRUSTED_PLUGIN_PLUGIN_H_
@@ skipping 148 matching lines @@
   void SignalStartSelLdrDone(int32_t pp_error,
                              bool* started,
                              ServiceRuntime* service_runtime);
 
   // Signals that the nexe is started.
   // This is invoked on the main thread.
   void SignalNexeStarted(int32_t pp_error,
                          bool* started,
                          ServiceRuntime* service_runtime);
 
+  // This is invoked on the main thread.
   void LoadNexeAndStart(int32_t pp_error,
+                        ServiceRuntime* service_runtime,
                         PP_NaClFileInfo file_info,
-                        ServiceRuntime* service_runtime);
+                        const pp::CompletionCallback& callback);
 
   // Callback used when getting the URL for the .nexe file.  If the URL loading
   // is successful, the file descriptor is opened and can be passed to sel_ldr
   // with the sandbox on.
   void NexeFileDidOpen(int32_t pp_error);
   void NexeFileDidOpenContinuation(int32_t pp_error);
 
   // Callback used when the reverse channel closes.  This is an
   // asynchronous event that might turn into a JavaScript error or
   // crash event -- this is controlled by the two state variables
@@ skipping 44 matching lines @@
 
   PP_NaClFileInfo nexe_file_info_;
 
   const PPB_NaCl_Private* nacl_interface_;
   pp::UMAPrivate uma_interface_;
 };
 
 }  // namespace plugin
 
 #endif  // NATIVE_CLIENT_SRC_TRUSTED_PLUGIN_PLUGIN_H_