Add ChannelHandle::mojo_handle to mus' ChannelHandle mojom.

components/mus/public/interfaces/channel_handle.mojom

 // Copyright 2016 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.
 
 module mus.mojom;
 
 // See IPC::ChannelHandle in src/ipc/ipc_channel_handle.h
 struct ChannelHandle {

[dcheng, 2016/07/01 01:31:43]

Would it be possible to document this interface? For example, why does mus need
to do this? Naively, I would have imagined the underlying IPC stuff was Good
Enough.

[Anand Mistry (off Chromium), 2016/07/01 05:52:54]

I assume this is needed for GPU channels, which still use legacy IPC channels.

[dcheng, 2016/07/04 07:11:59]

mus team, can someone confirm? Is there a useful comment to add here?

[Peng, 2016/07/04 14:40:09]

Mus is using the existing GPU command buffer which uses Chrome IPC,
because we don't want to have and maintain two GPU command buffer
implementations.

   string name;
 
   // On POSIX, it is one endpoint of a socket pair. On Windows, it is not used.
   handle socket;
+
+  // Message pipe handle used for ChannelMojo.
+  handle<message_pipe>? mojo_handle;
 };