Remove custom scroll handling. (dart-lang#8581)

Author: isoos

pkg/web_app/lib/script.dart

@@ -16,7 +16,6 @@ import 'src/likes.dart';
 import 'src/mobile_nav.dart';
 import 'src/page_updater.dart';
 import 'src/screenshot_carousel.dart';
-import 'src/scroll.dart';
 import 'src/search.dart';
 import 'src/widget/widget.dart' show setupWidgets;
 
@@ -36,7 +35,6 @@ void main() {
 
 void _setupAllEvents() {
   setupSearch();
-  setupScroll();
   setupFoldable();
   setupHoverable();
   setupMobileNav();