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

ipc/ipc_message_macros.h

 // Copyright (c) 2006-2008 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.
 
 // This header is meant to be included in multiple passes, hence no traditional
 // header guard.
 //
 // In your XXX_messages_internal.h file, before defining any messages do:
 //     #define IPC_MESSAGE_START XMsgStart
 // XMstStart value is from the IPCMessageStart enum in ipc_message_utils.h, and
@@ skipping 342 matching lines @@
 #define IPC_SYNC_MESSAGE_ROUTED5_4_EXTRA(msg_class, type1_in, type2_in, type3_in, type4_in, type5_in, type1_out, type2_out, type4_out)
 
 #endif
 
 // Note: we currently use __LINE__ to give unique IDs to messages within a file.
 // They're globally unique since each file defines its own IPC_MESSAGE_START.
 // Ideally, we wouldn't use line numbers, but instead use the __COUNTER__ macro,
 // but it needs gcc 4.3 and xcode doesn't use it yet.  When that happens, switch
 // to it.
 
+#define IPC_STRUCT_FIRST(type, name, init) \
+  struct IPC_STRUCT_NAME { IPC_STRUCT_NAME (); ~IPC_STRUCT_NAME (); \
+    IPC_STRUCT_MEMBER(type, name)
+#define IPC_STRUCT_NEXT(type, name, init) \
+    IPC_STRUCT_MEMBER(type, name)
+#define IPC_STRUCT_LAST(type, name, init) \
+    IPC_STRUCT_MEMBER(type, name) \
+  }; \
+  namespace IPC { \
+    template <> \
+    struct ParamTraits<IPC_STRUCT_NAME> { \
+      typedef IPC_STRUCT_NAME param_type; \
+      static void Write(Message* m, const param_type& p); \
+      static bool Read(const Message* m, void** iter, param_type* p); \
+      static void Log(const param_type& p, std::string* l); \
+    }; \
+  }
+#define IPC_STRUCT_MEMBER(type, name) type name;
+
 #define IPC_MESSAGE_CONTROL0(msg_class) \
   class msg_class : public IPC::Message { \
    public: \
    enum { ID = (IPC_MESSAGE_START << 16) + __LINE__ }; \
     msg_class() \
         : IPC::Message(MSG_ROUTING_CONTROL, \
                        ID, \
                        PRIORITY_NORMAL) {} \
   }; \
   IPC_MESSAGE_CONTROL0_EXTRA(msg_class)
@@ skipping 863 matching lines @@
   } \
 }
 
 #define IPC_END_MESSAGE_MAP_EX() \
   } \
 }
 
 // This corresponds to an enum value from IPCMessageStart.
 #define IPC_MESSAGE_CLASS(message) \
   message.type() >> 16