Make the implementation .cc files go away, instead have the authors give us a...

ipc/param_traits_write_macros.h

+// Copyright (c) 2011 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 IPC_PARAM_TRAITS_WRITE_MACROS_H_
+#define IPC_PARAM_TRAITS_WRITE_MACROS_H_
+
+// Null out all the macros that need nulling.
+#include "ipc/ipc_message_null_macros.h"
+
+// STRUCT declarations cause corresponding STRUCT_TRAITS declarations to occur.
+#undef IPC_STRUCT_BEGIN
+#undef IPC_STRUCT_MEMBER
+#undef IPC_STRUCT_END
+#define IPC_STRUCT_BEGIN(struct_name) IPC_STRUCT_TRAITS_BEGIN(struct_name)
+#define IPC_STRUCT_MEMBER(type, name) IPC_STRUCT_TRAITS_MEMBER(name)
+#define IPC_STRUCT_END() IPC_STRUCT_TRAITS_END()
+
+// Set up so next include will generate write methods.
+#undef IPC_STRUCT_TRAITS_BEGIN
+#undef IPC_STRUCT_TRAITS_MEMBER
+#undef IPC_STRUCT_TRAITS_END
+#define IPC_STRUCT_TRAITS_BEGIN(struct_name) \
+  void ParamTraits<struct_name>::Write(Message* m, const param_type& p) {
+#define IPC_STRUCT_TRAITS_MEMBER(name) WriteParam(m, p.name);
+#define IPC_STRUCT_TRAITS_END() }
+
+#undef IPC_ENUM_TRAITS
+#define IPC_ENUM_TRAITS(enum_name) \
+  void ParamTraits<enum_name>::Write(Message* m, const param_type& p) { \
+    m->WriteInt(static_cast<int>(p)); \
+  }
+
+#endif  // IPC_PARAM_TRAITS_WRITE_MACROS_H_
+