Reverting in an attempt to fix Win Builder 2010 (dbg).

ipc/ipc_message_macros.h

Index: ipc/ipc_message_macros.h
===================================================================
--- ipc/ipc_message_macros.h	(revision 122697)
+++ ipc/ipc_message_macros.h	(working copy)
@@ -1,4 +1,4 @@
-// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// 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.
 
@@ -173,14 +173,6 @@
 //     ViewHostMsg_SyncMessageName::WriteReplyParams(reply_msg, out1, out2);
 //     Send(reply_msg);
 
-// Files that want to export their ipc messages should do
-//   #undef IPC_MESSAGE_EXPORT
-//   #define IPC_MESSAGE_EXPORT VISIBILITY_MACRO
-// after including this header, but before using any of the macros below.
-// (This needs to be before the include guard.)
-#undef IPC_MESSAGE_EXPORT
-#define IPC_MESSAGE_EXPORT
-
 #ifndef IPC_IPC_MESSAGE_MACROS_H_
 #define IPC_IPC_MESSAGE_MACROS_H_
 
@@ -192,6 +184,11 @@
 #include "ipc/ipc_message_utils_impl.h"
 #endif
 
+// Override this to force message classes to be exported.
+#ifndef IPC_MESSAGE_EXPORT
+#define IPC_MESSAGE_EXPORT
+#endif
+
 // Macros for defining structs.  May be subsequently redefined.
 #define IPC_STRUCT_BEGIN(struct_name) \
   IPC_STRUCT_BEGIN_WITH_PARENT(struct_name, IPC::NoParams)