ChannelMojo: Replace hand written messsages with mojo.

ipc/mojo/client_channel.mojom

Index: ipc/mojo/client_channel.mojom
diff --git a/mojo/examples/echo/echo_service.mojom b/ipc/mojo/client_channel.mojom
similarity index 62%
copy from mojo/examples/echo/echo_service.mojom
copy to ipc/mojo/client_channel.mojom
index 6e23c6d4247e74a561526ffbce438e22967fd8f0..b2da0d40e705f898ca4522339c549c135b997a3e 100644
--- a/mojo/examples/echo/echo_service.mojom
+++ b/ipc/mojo/client_channel.mojom
@@ -2,10 +2,10 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-module mojo.examples {
+module IPC {
 
-interface EchoService {
-  EchoString(string? value) => (string? value);
+interface ClientChannel {
+  Init(handle<message_pipe> pipe, int32 peer_pid) => (int32 pid);
 };
 
 }