ash: Fix app launcher closing on uninstall dialog.

BUG=303267,276513
TEST=Covered by AppListControllerTest.*
R=flackr@chromium.org, jamescook@chromium.org

Review URL: https://codereview.chromium.org/25708010

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@226942 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 226942