Implement Non-Closable Notification

ui/message_center/views/notification_view.h

Index: ui/message_center/views/notification_view.h
diff --git a/ui/message_center/views/notification_view.h b/ui/message_center/views/notification_view.h
index 491080cfbeb7e49868d08053075101e90aee9bda..2e69a083a9864c9899f8bc7d8d12433195c72074 100644
--- a/ui/message_center/views/notification_view.h
+++ b/ui/message_center/views/notification_view.h
@@ -62,6 +62,9 @@ class MESSAGE_CENTER_EXPORT NotificationView
   // Overridden from MessageView:
   void UpdateWithNotification(const Notification& notification) override;
   void ButtonPressed(views::Button* sender, const ui::Event& event) override;
+  bool IsCloseButtonFocused() override;
+  void RequestFocusOnCloseButton() override;
+  bool IsClosable() override;
 
   // Overridden from MessageViewController:
   void ClickOnNotification(const std::string& notification_id) override;
@@ -105,6 +108,7 @@ class MESSAGE_CENTER_EXPORT NotificationView
   void CreateOrUpdateIconView(const Notification& notification);
   void CreateOrUpdateImageView(const Notification& notification);
   void CreateOrUpdateActionButtonViews(const Notification& notification);
+  void CreateOrUpdateCloseButtonView(const Notification& notification);
 
   int GetMessageLineLimit(int title_lines, int width) const;
   int GetMessageHeight(int width, int limit) const;
@@ -133,6 +137,7 @@ class MESSAGE_CENTER_EXPORT NotificationView
   ProportionalImageView* image_view_;
   NotificationProgressBarBase* progress_bar_view_;
   std::vector<NotificationButton*> action_buttons_;
+  scoped_ptr<views::ImageButton> close_button_;
   std::vector<views::View*> separators_;
 
   DISALLOW_COPY_AND_ASSIGN(NotificationView);