Pass the nacl start parameters as a struct.

chrome/common/nacl_messages.h

 // 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.
 
 // Defines messages between the browser and NaCl process.
 
 // Multiply-included message file, no traditional include guard.
 #include "base/process.h"
 #include "chrome/common/nacl_types.h"
 #include "ipc/ipc_message_macros.h"
 
-#ifndef CHROME_COMMON_NACL_MESSAGES_H_
-#define CHROME_COMMON_NACL_MESSAGES_H_
+#define IPC_MESSAGE_START NaClMsgStart
 
-#endif  // CHROME_COMMON_NACL_MESSAGES_H_
-
-#define IPC_MESSAGE_START NaClMsgStart
+IPC_STRUCT_TRAITS_BEGIN(nacl::NaClStartParams)
+  IPC_STRUCT_TRAITS_MEMBER(sockets)
+  IPC_STRUCT_TRAITS_MEMBER(validation_cache_key)
+  IPC_STRUCT_TRAITS_MEMBER(version)
+  IPC_STRUCT_TRAITS_MEMBER(enable_exception_handling)
+IPC_STRUCT_TRAITS_END()
 
 //-----------------------------------------------------------------------------
 // NaClProcess messages
 // These are messages sent between the browser and the NaCl process.
 // Tells the NaCl process to start.
-IPC_MESSAGE_CONTROL4(NaClProcessMsg_Start,
-                     std::vector<nacl::FileDescriptor> /* sockets */,
-                     std::string /* validation_cache_key */,
-                     std::string /* version */,
-                     bool /* enable_exception_handling */)
+IPC_MESSAGE_CONTROL1(NaClProcessMsg_Start,
+                     nacl::NaClStartParams /* params */)
 
 // Tells the NaCl broker to launch a NaCl loader process.
 IPC_MESSAGE_CONTROL1(NaClProcessMsg_LaunchLoaderThroughBroker,
                      std::string /* channel ID for the loader */)
 
 // Notify the browser process that the loader was launched successfully.
 IPC_MESSAGE_CONTROL2(NaClProcessMsg_LoaderLaunched,
                      std::string,  /* channel ID for the loader */
                      base::ProcessHandle /* loader process handle */)
 
@@ skipping 15 matching lines @@
 // Used by the NaCl process to query a database in the browser.  The database
 // contains the signatures of previously validated code chunks.
 IPC_SYNC_MESSAGE_CONTROL1_1(NaClProcessMsg_QueryKnownToValidate,
                             std::string, /* A validation signature */
                             bool /* Can validation be skipped? */)
 
 // Used by the NaCl process to add a validation signature to the validation
 // database in the browser.
 IPC_MESSAGE_CONTROL1(NaClProcessMsg_SetKnownToValidate,
                      std::string /* A validation signature */)