arc-bridge: Add IPC message definitions

chromeos/arc/bridge/common/arc_host_messages.h

Index: chromeos/arc/bridge/common/arc_host_messages.h
diff --git a/chromeos/arc/bridge/common/arc_host_messages.h b/chromeos/arc/bridge/common/arc_host_messages.h
new file mode 100644
index 0000000000000000000000000000000000000000..c68edf6f87b462cb1eaf2c48d36b66c282fdae4d
--- /dev/null
+++ b/chromeos/arc/bridge/common/arc_host_messages.h
@@ -0,0 +1,15 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.

[Shuhei Takahashi, 2015/10/26 11:13:40]

Why did you decide to have two message definition files? As you see in
ipc_message_start.h, it is a rare case.

[Luis Héctor Chávez, 2015/10/26 21:03:27]

To make it possible to add messages to the code without having the generated
message IDs for other messages change (by only appending to these files).

+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Messages sent from the host to the ARC instance
+// Multiply-included message file, hence no include guard.
+
+#include <stdint.h>
+
+#include "ipc/ipc_message_macros.h"
+
+#define IPC_MESSAGE_START ArcHostMsgStart
+
+IPC_MESSAGE_CONTROL0(ArcHostMsg_Pong)

[Shuhei Takahashi, 2015/10/26 11:13:40]

Typically this should be named as ArcInstanceHostMsg_*. I looked for chromium
codebase but could not find an exceptional naming like this.

[Luis Héctor Chávez, 2015/10/26 21:03:27]

Done

+IPC_MESSAGE_CONTROL0(ArcHostMsg_InstanceReady)