European shares close slightly higher ahead of Christmas shutdown; Aviva to buy Direct Line in $4.6 billion deal - Direct Line Shares Rise on Revised Aviva Bid - Direct Line set to accept sweetened Aviva takeover bid - Aviva Reaches Preliminary Deal With Direct Line on Takeover - Aviva raises offer to buy Direct Line - Direct Line Shares Surge 40% as it Rejects Aviva Offer - Why Direct Line Should Accept Aviva's Offer - Direct Line shares soar as it rejects UK rival's £3.3bn takeover offer - Europe stocks close higher; Direct Line soars 41% after rejecting Aviva bid - Direct Line shares surge 37% after insurer rejects Aviva bid