Retrieve pinned flag directly from Notification class

ui/message_center/views/custom_notification_view.cc

Index: ui/message_center/views/custom_notification_view.cc
diff --git a/ui/message_center/views/custom_notification_view.cc b/ui/message_center/views/custom_notification_view.cc
index a648f83614afb3ca42dddeb698fcfd7f6ab7c35d..42d8f8ee6f0614170d485960f187e897aa3d7744 100644
--- a/ui/message_center/views/custom_notification_view.cc
+++ b/ui/message_center/views/custom_notification_view.cc
@@ -75,12 +75,6 @@ void CustomNotificationView::RequestFocusOnCloseButton() {
     contents_view_delegate_->RequestFocusOnCloseButton();
 }
 
-bool CustomNotificationView::IsPinned() const {
-  if (!contents_view_delegate_)
-    return false;
-  return contents_view_delegate_->IsPinned();
-}
-
 const char* CustomNotificationView::GetClassName() const {
   return kViewClassName;
 }