Ensure sidebar links are re-enabled when a confirmation dialog is closed

Confirmation dialogs should have the BrowserOptions  page as their parent.
If they do not, closing a confirmation dialog will not re-enable the
sidebar links (History/Extensions/Settings/Help).

The parent used to be set correctly but got lost accidentally in the
refactor of crrev.com/163874.

BUG=158912

Review URL: https://codereview.chromium.org/11366083

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@166023 0039d316-1c4b-4281-b951-d872f2087c98
1 file changed