use variadic macros/templates in IPC message implementation

content/renderer/render_thread_impl_browsertest.cc

Index: content/renderer/render_thread_impl_browsertest.cc
diff --git a/content/renderer/render_thread_impl_browsertest.cc b/content/renderer/render_thread_impl_browsertest.cc
index a7151aaa4a5fa9d61811e7d769a63ef0d41c6e2c..f404cd8bcc755eeb3feb531fc7dcf88f2545d677 100644
--- a/content/renderer/render_thread_impl_browsertest.cc
+++ b/content/renderer/render_thread_impl_browsertest.cc
@@ -27,8 +27,12 @@
 
 // IPC messages for testing ----------------------------------------------------
 
+// TODO(mdempsky): Fix properly.

[danakj, 2015/12/19 00:15:05]

Can you leave more context, what is properly?

[mdempsky, 2015/12/19 02:14:48]

"Properly" here is creating browsertest_messages.h and
browsertest_messages_generator.cc and doing the full #include ritual like in
content/common/content_message_generator.cc.

The problem here is that ipc/ipc_messages_macro.h has already been #include'd by
the FOO_messages.h headers included above, so defining IPC_MESSAGE_IMPL here
wasn't doing anything.  It happened to work only because it's only used for
TestMsg_QuitRunLoop, which is a 0-argument async message, and the macros before
happened to implement enough of those even without IPC_MESSAGE_IMPL for this
file to work.

+#undef IPC_IPC_MESSAGE_MACROS_H_
+#undef IPC_MESSAGE_EXTRA
 #define IPC_MESSAGE_IMPL
 #include "ipc/ipc_message_macros.h"
+#include "ipc/ipc_message_templates_impl.h"
 
 #undef IPC_MESSAGE_START
 #define IPC_MESSAGE_START TestMsgStart