Fix problems restoring profiles from User Manager.

Browser windows launched from the User Manager were marked "startup" if no other browser windows were open but this breaks expectations elsewhere in the code that a profile has gone through a full shut-down and start-up when this flag is set (specifically that all files have been closed and current/last versions have been rotated).

BUG=330037

Review URL: https://codereview.chromium.org/131783010

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@249574 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 249574