Simplify the magic required to create IPC message headers a bit.

chrome/common/plugin_messages.cc

 // Copyright (c) 2010 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.
 
-#include "chrome/common/plugin_messages.h"
-
 #include "base/utf_string_conversions.h"
 #include "ipc/ipc_channel_handle.h"
 
-#define MESSAGES_INTERNAL_IMPL_FILE \
-  "chrome/common/plugin_messages_internal.h"
-#include "ipc/ipc_message_impl_macros.h"
+#define IPC_MESSAGE_IMPL
+#include "chrome/common/plugin_messages.h"
 
 PluginMsg_Init_Params::PluginMsg_Init_Params()
     : containing_window(0),
       load_manually(false),
       host_render_view_routing_id(-1) {
 }
 
 PluginMsg_Init_Params::~PluginMsg_Init_Params() {
 }
 
@@ skipping 285 matching lines @@
   l->append(", ");
   LogParam(p.transparent, l);
 #if defined(OS_MACOSX)
   l->append(", ");
   LogParam(p.ack_key, l);
 #endif
   l->append(")");
 }
 
 }  // namespace IPC