GitLab

GuestViews are registered and re-registered on a per-profile basis.
This would cause a DCHECK to fire. Make registration lazy and once on first
GuestView creation.

BUG=none
TBR=fsamuel@chromium.org

Review URL: https://codereview.chromium.org/409133002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@284723 0039d316-1c4b-4281-b951-d872f2087c98