ash: Move ShelfWindowTargeter construction from ShelfWidget to RootWindowController

ash: Move ShelfWindowTargeter construction from ShelfWidget to RootWindowController

This eliminates aura::Window dependencies from ShelfWidget, which we need to do
to get it running in mus/mash.

mus will need a different implementation of this feature.

BUG=615155, 636010
TEST=existing ash_unittests for ShelfWidget

Committed: https://crrev.com/752e8df8664956328150560c93c13e3c00a6987f
Cr-Commit-Position: refs/heads/master@{#410781}

[James Cook, 2016-08-09 18:16:16]

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

[commit-bot: I haz the power, 2016-08-09 18:16:47]

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

[James Cook, 2016-08-09 18:17:17]

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

[James Cook, 2016-08-09 18:17:18]

msw, please take a look.

[msw, 2016-08-09 18:55:19]

lgtm

[commit-bot: I haz the power, 2016-08-09 19:01:20]

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

[commit-bot: I haz the power, 2016-08-09 19:01:21]

Dry run: This issue passed the CQ dry run.

[James Cook, 2016-08-09 19:27:19]

The CQ bit was checked by jamescook@chromium.org

[commit-bot: I haz the power, 2016-08-09 19:28:34]

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, 2016-08-09 19:54:55]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-08-09 19:57:34]

Description was changed from

==========
ash: Move ShelfWindowTargeter construction from ShelfWidget to
RootWindowController

This eliminates aura::Window dependencies from ShelfWidget, which we need to do
to get it running in mus/mash.

mus will need a different implementation of this feature.

BUG=615155,636010
TEST=existing ash_unittests for ShelfWidget
==========

to

==========
ash: Move ShelfWindowTargeter construction from ShelfWidget to
RootWindowController

This eliminates aura::Window dependencies from ShelfWidget, which we need to do
to get it running in mus/mash.

mus will need a different implementation of this feature.

BUG=615155,636010
TEST=existing ash_unittests for ShelfWidget

Committed: https://crrev.com/752e8df8664956328150560c93c13e3c00a6987f
Cr-Commit-Position: refs/heads/master@{#410781}
==========

[commit-bot: I haz the power, 2016-08-09 19:57:35]

Patchset 1 (id:??) landed as
https://crrev.com/752e8df8664956328150560c93c13e3c00a6987f
Cr-Commit-Position: refs/heads/master@{#410781}