Check that BlockedContents::blocked_popup_container is not NULL before using it.
Check that BlockedContents::blocked_popup_container is not NULL before using it.

BUG=53176
TEST=None.
Review URL: http://codereview.chromium.org/3204003

git-svn-id: http://src.chromium.org/svn/trunk/src@57249 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: 96498597323af5b0db7de0f7e7efc272c24d72da
meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser