Revert of Show message center on lock screen

ui/message_center/notification_list.h

Index: ui/message_center/notification_list.h
diff --git a/ui/message_center/notification_list.h b/ui/message_center/notification_list.h
index f52217b0787b9dde14c367812112e7533f2851b6..6b30a2ebbf73ae78803c68d1e15047e911ece57e 100644
--- a/ui/message_center/notification_list.h
+++ b/ui/message_center/notification_list.h
@@ -56,13 +56,14 @@
   // toasts.
   typedef std::set<Notification*, CompareTimestampSerial> PopupNotifications;
 
-  explicit NotificationList(MessageCenter* message_center);
+  explicit NotificationList();
   virtual ~NotificationList();
 
-  // Makes a message "read". Collects the set of ids whose state have changed
-  // and set to |udpated_ids|. NULL if updated ids don't matter.
-  void SetNotificationsShown(const NotificationBlockers& blockers,
-                             std::set<std::string>* updated_ids);
+  // Affects whether or not a message has been "read". Collects the set of
+  // ids whose state have changed and set to |udpated_ids|. NULL if updated
+  // ids don't matter.
+  void SetMessageCenterVisible(bool visible,
+                               std::set<std::string>* updated_ids);
 
   void AddNotification(std::unique_ptr<Notification> notification);
 
@@ -136,6 +137,8 @@
   size_t NotificationCount(const NotificationBlockers& blockers) const;
   size_t UnreadCount(const NotificationBlockers& blockers) const;
 
+  bool is_message_center_visible() const { return message_center_visible_; }
+
  private:
   friend class NotificationListTest;
   FRIEND_TEST_ALL_PREFIXES(NotificationListTest,
@@ -148,8 +151,8 @@
 
   void PushNotification(std::unique_ptr<Notification> notification);
 
-  MessageCenter* message_center_;  // owner
   Notifications notifications_;
+  bool message_center_visible_;
   bool quiet_mode_;
 
   DISALLOW_COPY_AND_ASSIGN(NotificationList);