chromeos: Notify window manager about signout.

chromeos: Notify window manager about signout.

This makes us send a message to the window manager when the
user is logging out so the window manager can display a more
graceful transition (currently, you can sometimes see the
browser windows getting closed one by one).

The power manager already sends a similar message to the
window manager when we're shutting down.

BUG=chromium-os:9915
TEST=built and tried it with an updated window manager.  try bots pass too

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=70270

[Daniel Erat, 2010-12-22 23:43:12]

My buildbot run failed.  Do cros_deps updates need to be checked in in a
separate change from the code that uses them, at least to get things to pass on
the buildbot?

[Chris Masone, 2010-12-23 00:26:58]

On 2010/12/22 23:43:12, Daniel Erat wrote:
> My buildbot run failed.  Do cros_deps updates need to be checked in in a
> separate change from the code that uses them, at least to get things to pass
on
> the buildbot?

Hm.  That kinda defeats the purpose of having cros.DEPS/DEPS in the main tree. 
I admit that I don't know how the trybots deal with DEPS rolls.  I _think_ they
just sync to LKGR and apply your patch, which would mean that it never processes
the DEPS change.  I wonder if there's a way to force it to apply your change and
sync or soemthing...maybe a trooper would know?

[Daniel Erat, 2010-12-29 16:26:18]

Another look?

[Chris Masone, 2010-12-29 18:20:48]

On 2010/12/29 16:26:18, Daniel Erat wrote:
> Another look?

LGTM