FBTF: Reapplies r55259, the first new IPC definition patch.

ipc/ipc_message_utils_impl.h

Index: ipc/ipc_message_utils_impl.h
diff --git a/ipc/ipc_message_utils_impl.h b/ipc/ipc_message_utils_impl.h
new file mode 100644
index 0000000000000000000000000000000000000000..ba11990f97633c153afe2f85ca2181713b7890e3
--- /dev/null
+++ b/ipc/ipc_message_utils_impl.h
@@ -0,0 +1,30 @@
+// Copyright (c) 2010 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 file contains templates forward declared (but not defined) in
+// ipc_message_utils.h so that they are only instantiated in certain files,
+// notably ipc_message_impl_macros.h and a few IPC unit tests.
+
+#ifndef IPC_IPC_MESSAGE_UTILS_IMPL_H_
+#define IPC_IPC_MESSAGE_UTILS_IMPL_H_
+
+namespace IPC {
+
+template <class ParamType>
+MessageWithTuple<ParamType>::MessageWithTuple(
+    int32 routing_id, uint32 type, const RefParam& p)
+    : Message(routing_id, type, PRIORITY_NORMAL) {
+  WriteParam(this, p);
+}
+
+// TODO(erg): Migrate MessageWithTuple<ParamType>::Read() here once I figure
+// out why having the definition here doesn't export the symbols.
+
+// We can't migrate the template for Log() to MessageWithTuple, because each
+// subclass needs to have Log() to call Read(), which instantiates the above
+// template.
+
+}  // namespace IPC
+
+#endif  // IPC_IPC_MESSAGE_UTILS_IMPL_H_