PPAPI/NaCl: Move plugin_main.cc's contents into irt_ppapi.cc

ppapi/nacl_irt/plugin_main.h

Index: ppapi/nacl_irt/plugin_main.h
diff --git a/ppapi/nacl_irt/plugin_main.h b/ppapi/nacl_irt/plugin_main.h
deleted file mode 100644
index 75fc1124affe4959cf580d6d8c281aaec2986a4d..0000000000000000000000000000000000000000
--- a/ppapi/nacl_irt/plugin_main.h
+++ /dev/null
@@ -1,25 +0,0 @@
-// Copyright 2014 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.
-
-#ifndef PPAPI_NACL_IRT_PLUGIN_MAIN_H_
-#define PPAPI_NACL_IRT_PLUGIN_MAIN_H_
-
-#include "ppapi/nacl_irt/public/irt_ppapi.h"
-#include "ppapi/proxy/ppapi_proxy_export.h"
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-// The entry point for the main thread of the PPAPI plugin process.
-PPAPI_PROXY_EXPORT int PpapiPluginMain(void);
-
-PPAPI_PROXY_EXPORT void PpapiPluginRegisterThreadCreator(
-    const struct PP_ThreadFunctions* new_funcs);
-
-#ifdef __cplusplus
-}
-#endif
-
-#endif  // PPAPI_NACL_IRT_PLUGIN_MAIN_H_