[Chromoting] Re-add call to chrome.app.window.current().close()

[Chromoting] Re-add call to chrome.app.window.current().close()

A recent change removed a call to close the app window because it seemed
redundant with the call in disconnect(), but that code path is not called
when the host initiates the disconnection.

This reverts the calling pattern to what it was before the aforementioned
change.

NOTRY=True
BUG=

Committed: https://crrev.com/0805b9c8b55ddf3e26f83d09e9bfc2cf5ba0b9f4
Cr-Commit-Position: refs/heads/master@{#312278}

[garykac, 2015-01-17 00:44:34]

garykac@chromium.org changed reviewers:
+ jamiewalch@chromium.org

[Jamie, 2015-01-17 00:54:34]

lgtm

[garykac, 2015-01-20 21:39:22]

The CQ bit was checked by garykac@chromium.org

[commit-bot: I haz the power, 2015-01-20 21:40:01]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/814133007/1

[commit-bot: I haz the power, 2015-01-20 21:41:30]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-01-20 21:42:30]

Patchset 1 (id:??) landed as
https://crrev.com/0805b9c8b55ddf3e26f83d09e9bfc2cf5ba0b9f4
Cr-Commit-Position: refs/heads/master@{#312278}