Wait for scroll before deciding whether to add scroll down button

FREEBIE

js/views/conversation_view.js

@@ -278,9 +278,13 @@
                 unreadEl.insertBefore(this.$('#' + oldestUnread.get('id')));
                 var position = unreadEl[0].scrollIntoView(true);
 
+                // scrollIntoView is an async operation, but we have no way to listen for
+                // completion of the resultant scroll.
+                setTimeout(function() {
                     if (this.view.bottomOffset > 0) {
                         this.addScrollDownButtonWithCount(unreadCount);
                     }
+                }.bind(this), 1);
             }
         },