Remove ash::ScopedObserverWithDuplicatedSources

Remove ash::ScopedObserverWithDuplicatedSources

It was added in http://crrev.com/21185004 to allow observation of multiple
ActivationClients in ash. However, ash only has a single ActivationClient, so
just observe that directly.

This eliminates ash::WindowTreeHostManager access in ShelfWindowWatcher, which
will simplify its conversion to wm types. It also simplifies
BrowserStatusMonitor, which no longer needs to observe root windows or displays
just to add activation client observers.

BUG=629257
TEST=ash_unittests, chrome unit_tests, manually activate windows and tabs in
ash and verify shelf light-bar appearance changes correctly

Committed: https://crrev.com/04f84072e56506d52835408c0862a80865bde7b9
Cr-Commit-Position: refs/heads/master@{#407919}

[James Cook, 2016-07-26 17:48:30]

jamescook@chromium.org changed reviewers:
+ sky@chromium.org

[James Cook, 2016-07-26 17:48:31]

sky, please take a look.

There's more cleanup to do in ShelfWindowWatcher; I'm working on that now in a
dependent CL.

https://codereview.chromium.org/2185743002/diff/1/ash/shelf/shelf_window_watc...
File ash/shelf/shelf_window_watcher.cc (right):

https://codereview.chromium.org/2185743002/diff/1/ash/shelf/shelf_window_watc...
ash/shelf/shelf_window_watcher.cc:109:
Shell::GetInstance()->activation_client()->AddObserver(this);
This will get converted to WmShell in my next CL. I kept ash::Shell here to keep
this CL simpler.

[James Cook, 2016-07-26 17:48:37]

The CQ bit was checked by jamescook@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-07-26 17:49:04]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-07-26 18:36:48]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-07-26 18:36:49]

Dry run: This issue passed the CQ dry run.

[sky, 2016-07-26 21:03:13]

Nice! LGTM

[James Cook, 2016-07-26 21:20:49]

The CQ bit was checked by jamescook@chromium.org

[commit-bot: I haz the power, 2016-07-26 21:21:30]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-07-26 21:25:28]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-07-26 21:28:01]

Description was changed from

==========
Remove ash::ScopedObserverWithDuplicatedSources

It was added in http://crrev.com/21185004 to allow observation of multiple
ActivationClients in ash. However, ash only has a single ActivationClient, so
just observe that directly.

This eliminates ash::WindowTreeHostManager access in ShelfWindowWatcher, which
will simplify its conversion to wm types. It also simplifies
BrowserStatusMonitor, which no longer needs to observe root windows or displays
just to add activation client observers.

BUG=629257
TEST=ash_unittests, chrome unit_tests, manually activate windows and tabs in
ash and verify shelf light-bar appearance changes correctly
==========

to

==========
Remove ash::ScopedObserverWithDuplicatedSources

It was added in http://crrev.com/21185004 to allow observation of multiple
ActivationClients in ash. However, ash only has a single ActivationClient, so
just observe that directly.

This eliminates ash::WindowTreeHostManager access in ShelfWindowWatcher, which
will simplify its conversion to wm types. It also simplifies
BrowserStatusMonitor, which no longer needs to observe root windows or displays
just to add activation client observers.

BUG=629257
TEST=ash_unittests, chrome unit_tests, manually activate windows and tabs in
ash and verify shelf light-bar appearance changes correctly

Committed: https://crrev.com/04f84072e56506d52835408c0862a80865bde7b9
Cr-Commit-Position: refs/heads/master@{#407919}
==========

[commit-bot: I haz the power, 2016-07-26 21:28:02]

Patchset 1 (id:??) landed as
https://crrev.com/04f84072e56506d52835408c0862a80865bde7b9
Cr-Commit-Position: refs/heads/master@{#407919}