Mojo: Add a RawChannel::EnqueueMessage() that can be overridden by subclasses.

Mojo: Add a RawChannel::EnqueueMessage() that can be overridden by subclasses.

This mostly adds a TODO for POSIX. (We want to actually send "real"
messages with FDs attached, which means that we have to "split" any
message with too many FDs into multiple messages.)

R=yzshen@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=272471

[yzshen1, 2014-05-22 23:23:55]

lgtm

[viettrungluu, 2014-05-22 23:24:02]

The CQ bit was checked by viettrungluu@chromium.org

[commit-bot: I haz the power, 2014-05-22 23:24:50]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/viettrungluu@chromium.org/297683012/1

[commit-bot: I haz the power, 2014-05-23 02:24:42]

FYI, CQ is re-trying this CL (attempt #1).
Please consider checking whether the failures are real,
and report flakes to chrome-troopers@google.com.
The failing builders are:
  ios_rel_device_ninja on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/ios_rel_device_ninja/...)

[commit-bot: I haz the power, 2014-05-23 10:40:32]

Change committed as 272471